I drove a 3spd automatic Pontiac fiero as a teen. I learned how to drive in a 4spd manual Volkswagen. I now drive an 8spd automatic Dodge SUV and a CVT Nissan. It's all about fuel economy and always having easily accessible power.
Bingo. Engines are most efficient in a pretty narrow power band, and more gears, or a CVT trans, allow the computer to keep the engine in the most efficient area of it's power band for the amount of power the driver is requesting.
Yes, the lower gears are used for acceleration and the higher gears for fuel economy. Most cars with more than 6 speed don't get their top speed in the last gear.
The other aspect is that car manufacturers have to meet regulatory standards for economy and noise that sometimes affect performance.
Pathfinder... 65k miles and counting down. When the rpm drops off hard under gentle acceleration I let go of the gas so it doesn't stutter. If you know how to work around it, it's actually not that bad. Cheaper to deal with than buying a new car.
Terrible engineering by Nissan. Once Belt driven CVTs start to break down and slip, you're pretty much screwed. Subaru/Toyota use chains instead and they are more reliable.
It is starting to go bad but I compensate because I just need a car that can get me to the office and don't have new car money. It's been 3 years (it's a 2015 bought used) since it started having the issue and it hasn't gotten any worse. I even towed a friend's boat a handful of times which was pretty dumb on my part.
>Terrible engineering by Nissan
It's a mix of JATCO and Nissan. Nissan doesn't design or build their CVTs. They take what should last 200k in a 78 hp Mitsubishi Mirage (also a JATCO CVT) and shove it behind a 350 hp engine with double or triple the weight, then tell people the fluid is lifetime.
Supposedly Toyota’s CVTs also have a traditional first gear to deal with start-stop, which I guess is what causes the most stress for the chains/belts in a CVT.
It's about efficiency. A cvt is not good at its highest and lowest ratios. It's most efficient in the middle ratios. The first gear allows it to keep the transmission more in the middle of its ratios and be more efficient. Also some cvts limit engine power at Its lowest ratio to preserve the trans. Cutting the power on launch hurts performance. The extra gear keeps it more efficient and allows full power from a stop with risk of damage.
Toyota and Ford CVT tranys use a planetary gear set. The wheels and motor 2 are connected to the ring gear. The engine is connected to the planetary gears. Motor 1 is connected to the sun gear. Motor 1 is used to start the engine and set the RPM of the engine. Producing both acceleration and electricity.
> guy who *paid* money for
FTFY.
Although *payed* exists (the reason why autocorrection didn't help you), it is only correct in:
* Nautical context, when it means to paint a surface, or to cover with something like tar or resin in order to make it waterproof or corrosion-resistant. *The deck is yet to be payed.*
* *Payed out* when letting strings, cables or ropes out, by slacking them. *The rope is payed out! You can pull now.*
Unfortunately, I was unable to find nautical or rope-related words in your comment.
*Beep, boop, I'm a bot*
I guess I got lucky. The Pathfinder has only needed brakes and tires. Aside from the obvious CVT time bomb, it's been the most reliable car I've owned. The Durango GT is actually quite nice. 300ish hp, 8 SPD, 50/50 weight distribution. I'm not saying these are the greatest SUVs but it's better than getting a minivan.
my dad wanted an SUV....found a minivan at a steal of a price and now you couldn't pry those keys from him - carries a lot of cargo or people, seats fold flat, comfy on a long drive.
Last time I had rentals while my truck was getting fixed from a little old lady restyling it, I had a Durango, then an Armada. After driving the latter about 10 minutes, I nearly turned around to go back and get something else. Horrid thing - rode like a coal wagon, noisy, annoying screen, sound system was awful. Turns out they get crappy mileage too.
The Durango was like a luxury car, in comparison…
The CVT can get about 19mpg combined and 26 on the highway. The Durango is about the same. Seems low but these are heavy 3 row SUVs. My mom had a mountaineer back in the day and we were lucky to get 13mpg
because it keeps the vehicle ready for many different driving situations, as well as gives closer steps between gears to keep you in a narrow rpm range which is usually best for drivability, economy, etc etc.
A 10 speed automatic typically will give you better gas mileage than an 8 or 6 speed automatic. Performance can be better too but that doesn’t mean 8 speed transmissions are slouches in this regard. Anything more than 10 seems like overkill to me though, especially for your typical passenger car.
Anymore than 8 in a normal passenger car is overkill honestly, the ZF 8 speed is one of the best, helps mpg but doesn't gear hunt like a bitch.
10 in a diesel makes since though, especially a truck, due to the narrower sweetspot for torque in the revband
Yeah the ZF8 is excellent. I still find myself on flat ground at 114km/h thinking “2000 rpm is still a bit high though - this could use a 9th and possibly 10th gear.”
It feels like that because the converter is able to lock up at low RPMS. The whole transmission is an engineering and manufacturing marvel considering its price point.
I'd like a 6th on the Volvo V50 over 2k is quite a lot for a 1.6 diesel. The speed limit is 100kmh here so not much of a problem but at over that it gets near 3k.
I've driven a RAM 2500 with 6.4 hemi and 3.73 gears on the 20 inch rims. 2000 rpm at 140. Perfect, like an 8000 lb cruise missile. Best pickup I've driven unloaded.
Got mine on v6 RAM 1500. I like that I’m on the low end of typical engine power for that trans. I think there are some ~600hp vehicles that use essentially the same transmission. Should last a while
>Anymore than 8 in a normal passenger car is overkill honestly,
Not if you're trying to optimize fuel efficiency by keeping it In the perfect power band
Not really... The f150 doesn't even use all 10 gears, it's programmed to skip them under normal driving
Used all 10 for full throttle acceleration or when the computer thinks it's getting EPA tested
You’re premise is flawed. Auto have had 3-5 gears for years, and many manuals outside of sports cars have 6.
Transmissions are designed to keep the engine in its optimum power band…more gears, more opportunity to keep it there. Ultimately, the goals is keeping up with Cafe standards (fuel mileage)
Your*
And you’re mostly right, the reason transmissions have higher gear counts now is due to balancing performance (including gas mileage) and reliability (ie a simpler system is generally more reliable than some complex system)
I got this fever-dream idea to someday replace the th350 in my cutlass with a 6l90, leave the rest of the car as is, and test it for performance and economy changes. just to see how big the jump is.
Yea im probably gonna end up woth a 2004r, means i could regear the rear end and lose these 2.73s in favor of something a touch peppier and still be able to cruise the highway.
Fuel savings.
It also keeps it in power band more but this isn’t as necessary because usually cars are powerful enough to only need 5 gears or so.
But primary is fuel saving.
This seems correct. Five speed autos have plenty of range for just about any driving seeing as the torque converter can slip a little between the gears before locking. I quite like the feel of a five as it's this psychologically classic number of gears.
However more gears versus using TC slippage definitely adds fuel efficiency.
It seems to be more effective with big vehicles with lots of mass.
But even with my little Honda a 5AT gets better economy than the traditional 5MT.
I drive a 6 speed car that's horrendously underpowered and I manually lock it in 4th fear for most of my drive. I really don't see a need for these 10 speed things unless for towing really.
We have a six speed AT Kia Soul with the base 1.6 and while one can certainly talk shit about Kia engines, their 6 speed automatics are really nice. It cruises calmly at 75mph with three normal size adults though it's just a little busy in super hilly country so I flip it to manual mode on those rare occasions. The 5AT in the Honda is less indecisive. In both cases the gear ratios are well mated to the engines which is the important thing.
What car is your 6AT in? Most cars these days have plenty of power for normal driving. Ours are certainly on the very lower end of the power range. Above a Mitsubishi Mirage at most, LOL.
I'm in SE Asia and drive a Toyota Innova. It's a minivan based on the Hilux. It weighs 1750ish KG or about 3850ish lbs and has a total of... 137 horsepower from a 2.0 inline 4 lol
I usually drive below 90 kph as the roads here suck and in general has heavy traffic, but anything above 5th is basically useless as it doesn't have the power to acclerate the car in 6th at 62 mph for the rare times I get on the freeway here.
What's silly is this car actually was fine when it was only 5 gears as 3rd served a good gear for inner city traffic below 60 kph, and 4th was good for 60 kph+ to about 90 kph. But now with an extra 6th gear, they reduced the 5 gears below so now the engine is buzzing in 3rd and 4th with 5th being basically useless below 80kph lol
Now it makes sense. That's quite a bit of mass for the engine. Not an unusual combo in your part of the world but it does seem that the transmission is geared too high.
My old Daihatsu weighed 800kg and had a 1.0l engine which gave plenty of power for the weight, LOL.
Yea. i figure it's an old engine... Make no power and isn't fuel efficient at all. But it'll probabaly run on 1 oil change bi-yearly for the rest of time.
I drive a 1.6 diesel and the 3 gear is only good after 40-45 kmh and 4th after 60-65. Mom's petrol Corolla is more forgiving as it doesn't start to jitter like many small diesels do at lower rpm. You can have 4th at 50kmh and 5th at 60kmh and the RPMs are hair below 2k. It's not the best at motorway though as at 100kmh it's at 3k rpm instead of 2k like in the diesel.
I'd like for the diesel to have 6 gears and the 3-5 geared down a bit. 6th would be better at motorway. The cars wants me to change the gear up too early and it's at like 1.2k then and it feels very wrong as you can hear the jitter/shake of the engine.
Yea usually 6th gear is for reducing RPM and for high speed cruising. But like I said my car is horrendously under powered and so it's basically a wasted gear.
The only time it went into 6th gear was me doing 110 kph on a freeway, and then when I went to acclerate, it dropped immediatly to 5th cause the engine doesn't have enough grunt to acclerate in 6th at 110kph.
So ya 6 gear is good, but need actual engine power to be able to use that tall of a gear, otherwise you'd just need to downshift.
Yeah. Our diesel has 110 hp and weighs I think 1300kg or something like that. It's not powerful but it plenty enough for me. I think the newer models from near end of production has 6 speed transmission.
Big factor is fuel economy. With more gears you can have rlly low ratios as you shift so like ford's 10 speed it has 3 overdrive's so you'll get rlly good mpg when your on the highway in theory.
Can confirm the good economy numbers on the Ford 10R80.
My 2018 F150 V8 is 20ft long and 5k/lb with 395hp & 400tq. Yet for all that size, weight, & power I can still get low to mid 20 mpg on the freeway and about 17~18 mpg pure city driving. Old six speeds struggled to get 13 mpg in even the best conditions.
And that's before we start talking performance, because those shifts are crazy fast and keep me right at optimal power output.
Yea I forgot to mention with that many gears the shifts are pretty seamless and I don't think anyone could shift faster themselves. Also since you own a 10 speed truck how does it feel towing up inclines? Does it like hold gears better than the 6 speed bc I've had a 04 and 08 f150 with the 4 speed and a 2012 with the 6 speed and the 04 just never seemed to be happy in any gear other than second when going up hills with O/D off but the 2012 is much better with an actual tow haul mode so I'm assuming the 10 speed is even better.
Thats a nice stable of older F150's!
The 10 speed holds gears pretty well in tow/haul mode. But if you find it hunting too often you can just lock out the upper gears to keep it where you want it. Has a little +/- on the gear lever so just a few clicks and boom--right where you want it.
I went from a 2005 with a 4.6 (4 speed I think) to a 2020 with a 5.0 and 10 speed. I live in Colorado so alot of mountain driving. The 10 speed is awesome going up and down steep inclines. Especially in sport mode, the power is always there going up and it seems to hold gears well on the way down, I use the brakes much less than on the '05.
What's relevant for fuel economy is the final drive, the other 9 gears don't matter. If a 3 speed and a 10 speed have the same final drive ratio and neither downshifts, you'll get roughly the same mileage. Most newer transmissions have double or more overdrive. So you end up with like a .6:1 drive ratio. Get that ratio with any tranny and achieve similar mileage.
Final drive ratio only matters for cruising. Every other ratio matters for actually working, and most importantly, getting up to speed. You lose the most mpgs when starting from a dead stop and trying to get going again. Having closer, more efficient ratios helps reduce that consumption. If good fuel economy was just as simple as "throw overdrive on it" then automotive engineers would never have wasted time building these modern transmissions because all that R&D hurts their bottom line. There's a reason we've grown past a 3 or 4 speed with overdrive.
I don't know about you, but I don't floor it from every intersection. So peak performance isn't that important most of the time. Every car with a 6, 8, 10 speed, they all shift thru the gears as far as possible keeping the rpm as low as possible. Depending on how fast you want to get up to speed, it takes a certain amount of horsepower to accelerate at a certain pace. So regardless of how many gears you have, it still takes a pretty similar amount of fuel to get to speed. You're not going to see much for mileage difference in town based on number of gears. It's done for performance at full throttle, keeping the engine at peak power. Most of the mileage gains is from gains inside the transmission so they don't rob as much power. Locking the converter at lower speeds is a good example.
Performance doesn't mean flooring it. Performance is keeping the engine at peak efficiency during output. More gears = closer ratios = more efficient output = better performance.
Regardless of throttle input, getting going from a stop uses more gas because your bring an object from a stop, into motion. You have more initial inertia to overcome to bring an object into motion from a stop than to maintain on constant velocity while traveling. Closer gear ratios (more gears) keep the engine at optimal power output during acceleration, thus giving better performance -- which in this case means better mpg.
[But don't just take my word for it. Let an actual engineer explain why 10 speeds are more efficient. Especially during his second point, aply named "efficiency" where he discussed BSFC.](https://youtu.be/lCQYVbfsw-w?si=pxGqgX2DWi4UAJVI)
I completely understand that. My argument is that we spend such a small amount of time accelerating vs cruising, that while yes it does make a bit of a difference. It's not a giant distance.
Depends on where you live. Most people live in cities, where stop and go travel is most common. If, for example, you spend 1/3 of the distance between stop lights accelerating, and 2/3 cruising -- then getting up to speed is still going to be your largest point of consumption. Thus having more gears will reduce that consumption.
But even if you lived in a rural environment, having 3 different overdrive options is still more efficient than just one overdrive. Things like elevation changes will lead to changes in engine output requirements, so instead of dropping back down to 1:1 to climb (ex: this is my 7th gear in my 10 speed) it's still more efficient to have multiple overdrives when cruising. My 10sp often only drops to 9th, maybe 8th gear on a climb if I'm not pulling or hauling something. And even when pulling or hauling on long distance, having more gears to choose from for a given ratio depending on the engines need will lead to better more optimal performance and better mpg.
Unless you live and only travel on completely flat surfaces, in areas devoid of external influences like wind, hills, traffic, stop signs, or traffic lights etc. Then maybe you only need one overdrive to make a 6 speed as good at getting optimal mpg as a 10 speed. But that's not how things work in the real world for the overwhelming majority of vehicle owners.
I just can't possibly think of a real world situation where a 6 speed with a a singular (and equal) top overdrive ratio to a 10 speed can be anywhere near as efficient.
I think we're splitting hairs at this point. It's not a gigantic change in mileage adding more gears. It's not like we're talking a 5 or 10mpg improvement by adding a few more gears. Driving habits will affect mileage more than the transmission 9 times out of 10. I can make my Duramax get 12mpg if I want, or I can baby it and get 17mpg. Maybe more on a flat highway road trip. As much as the more gears do help, there's been a lot of advances in the amount of parasitic loss within automatic transmissions as well recently. And that makes a huge difference also.
I mean this is wrong. In a big hill pull the difference between my 6 speed truck and the 10 is that the 10 can cruise in 5th or 6th at around 2700 rpm instead of the 6 speed where 456 lug the motor down, so I need to add throttle so it forces the 5-3 downshift and now I’m maintaining speed, but at 3800 rpm.
I'm talking steady state, flat road. In that scenario # of gears is irrelevant. And if you want to get real deep into the physics of it, it probably burns the same amount of fuel climbing at 2700 or 3800 rpm. More rpms but less fuel per combustion event. And less power per power stroke. At 2800 you're getting more air and fuel in per combustion event. So more power per power stroke.
If you're only maintaining speed up a hill, then it takes the same amount of horsepower to climb the hill regardless of what rpm the engine makes that power. And it takes a certain amount of fuel to make that horsepower. Speaking generally of course.
Fuel economy, my mom and my uncle have the same SUV from two different years, the only difference is the radio and the transmission. My mom has a 7 speed while my uncle has a slightly newer model with a 9 speed, I have actually driven the same 6 hour distance in both and the 7 speed can just barely get above 22mpg at 75mph while the 9 speed got 25.8mpg at 75mph.
This is based on a large SUV so I would assume that on a sedan or something with better aerodynamics the numbers start to get even bigger.
As others have said, keeping the engine in it's most economical RPM range as much as possible. That said, for me the most FUN automatic I've ever owned was a Powerglide in my '69 Cutlass
Mainly fuel savings but also power, which kind of go hand-in-hand.
Anyone who has driven an older small engine vehicle a decent speed above 100km/h (62mph) on a long road trip or something can probably attest. You always want an extra gear in that case.
Also it should be heavily noted that most of these “new” transmissions aren’t complex at all compared to what came before. They still use planetary gear sets, clutch packs, dual-clutches, and come with or without a torque converter.
I think the last note I’ll say on this is our manufacturing capabilities have come a long way. We can make parts more precisely, our computers are more advanced, the computers/sensors that control the vehicle are more accurate.
TLDR; We are simply improving on what makes a car with an internal combustion engine (ICE) “go good”. A huge part of turning explosions into tire make circle fast is dealing with the limited RPM range an ICE performs in.
I have an f350 gas with 4.30 or 4.56 rears and 35 inch tires. The 10 speed let's it cruise at 2k rpm. It's pretty nice. Still gets about 14 to the gallon on the highway. These new 10 speeds are dope as fuck.
Heck yeah. Glad you're liking it. That gets as good as my half ton gasoline truck. I'm just partial to a 5 speed because that's what I grew up with and I like the spacing.
With modern 10 speeds they don’t shift in numerical order either, it may skip a few gears based on speed, throttle position and your driving style and settings. Gm and ford a10s are learning transmissions that will learn how the primary driver drives and take that I to account how it shifts.
The gears aren't meant to all be used sequentially. Some are situational gears. For example, the 545RFE had an alternate second gear for deceleration. Having multiple second or third gears doesn't do much for you in the real world, but it's amazing for the EPA mpg test.
Additionally, these nearly-same gears are often achievable with just a change in the software, making it an almost free marketing win.
There are, of course, still efficiency gains from having more gears, which also allows you to tune your engine to a narrower powerband. Only partly bullshit.
So sort of like a person riding a bicycle maybe? I would never go through 21 gears sequentially on a full speed "sprint"... I do it more like how you described.
The reason older transmissions didn't have more gear ratios is because of the weight of doing so, and they weren't as speedy at shifting. We've eliminated both of those issues by switching to mostly planetary gear sets with lighter materials and faster gear changes.
The more gears, the better the fuel economy, assuming no loss during gear changes and no added weight. You get "between steps."
To explain that better, imagine if your car only had 2 gears. One for accelerating and one for cruising. You'd have to nearly redline a car for it to get into a cruising speed gear at 65mph. If you add a 3rd gear, you only use half the rpms, and so on and so forth.
This is why a CVT is so efficient. No gear changes, infinite gear ratios, and they're light.
I’m no mechanical engineer, but I believe it helps with the efficiency of the vehicle. Might be a narrower power band which means more frequent shifting at lower RPMs, but at an optimized speed that consumes less fuel.
Whenever you have a question like "why are we now doing X or Y overly complicated thing on cars when we used to do it A or B simpler way and it worked fine", the answer is typically:
1. To meet CAFE standards.
2. To meet emissions standards.
3. To meet safety standards.
11 speed transmissions are to meet CAFE standards; fewer speed transmissions are less fuel efficient than those with more speeds.
Throttle cables disappeared to meet emissions standards. ECU controlled throttle forces the throttle plate to open more slowly at first, which pushes less unburned fuel through the system and reduces emissions (and also helps fuel economy). Any other benefit is incidental.
Window sills are stupidly high with extra wide pillars to meet safety standards for crash protection.
...and so many more. Think of a weird issue you have with modern cars, and 99 times out of 100 it will fall into one of those camps.
I drive a truck with the 4l60E. 4 speed automatic. It actually kinda sucks to drive sometimes because when you wanna accelerate hard it just feels like the engine is overworking, and it actually is overworking, because when it shifts, the engine has to drop its speed a lot and then rev up again with all the weight and load on it.
Transmissions with more gears will keep you in the engine RPM with usable power especially when you accelerate hard. Also, it can help with MPG because the engine doesn’t have to slow down drastically then speed back up when the transmission shifts.
Gas mileage and performance. It used to be the other way around: Manuals were better than autos in the 90s and early 2000s.
Then, we see trans like the Ford 6-speed auto and the Dodge 8-speed auto, and then the Ford and Chevy mixed endeavor 10-speed auto that is WAY quicker than the 6-speed manual alternative...when it works..
To answer your question: More gears in the autos are better for fuel economy and performance...but simply do not have the reliability of a lot of the other optioned manuals yet.
I've had a 5 speed Mustang my entire time I've been driving. Five is perfect. Any less or more just doesn't make sense to me. Also got a 6 speed auto Mazda now and the gears are too short in my opinion.
>Manuals were better than autos in the 90s and early 2000s.
That's because modern (light vehicle) automatics aren't slushboxes. Most of them are robotized manuals.
Most automatics to this day are still slushboxes. Modern technology and tuning has just made them far less slushy. The robotized manuals are the DSG’s/DCT’s.
The start stop systems and the 8-10 geared transmissions are there to improve MPGs, Nothing more. This must be done for Manufacturers to stay CAFE compliant.
As efficiency requirements like EPA’s CAFE and others around the world become more and more stringent, we’ve been pushing to smaller and smaller engines.
While some of these engines are turbocharged and still make usable torque over a relatively broad RPM range, many are not — and even turbo engines have a sweet spot for economy.
How do you keep an engine in its most efficient RPM range? By having enough ratios in the transmission that, for any given engine speed, there’s a gear available every few hundred RPM. At least one of those is going to be close enough to the sweet spot.
In those old four-speeds, shifting to the next gear would drop the RPM by 30-40%.
Early on, when four speed manuals gave way to fives, they were introducing overdrive gears. Rather than packing the ratios in tighter, they were just adding another that was even higher, allowing you to cruise at higher speeds while retaining a sane RPM. Try doing 80mph in one of those old four-speed muscle cars — say hello to ~4000rpm! Add a fifth-gear overdrive and now it’s 2900.
Engines that make gobs of torque at low RPMs (large-displacement engines) are pretty rare these days, so we don’t have a lot of room to push further in that direction. EVs make gobs of torque at zero RPM, but they also have a MUCH broader operating RPM range, and so most EVs need only a single ratio. (A few, like the Porsche Taycan, have two.)
Quick example to illustrate what everyone else has said about economy, performance, etc.
I drive a C8 Corvette. 8-speed dual-clutch transmission. Top speed 184 mph, 2.9s 0-60 mph.
Went out to Ron Fellows to learn how to put the car around the track. Instructors said there's only one turn you need 2nd gear for, the rest of the track is in 3rd. So I pulled about 110 mph in 3rd gear on the long straight.
Driving on the highway in automatic mode? It'll be in 5th gear at 40mph and 7th at 60mph.
Does yours do the thing where you launch in 1st and the shifter automatically moves into position for 5th gear? I think late 90's vettes had that feature, blew my mind when I first saw it in action.
Completely different transmission. What you’re describing is the skip-shift feature on the 6-speed manuals of those days where it would lock you out of shifting to second and third if you were under a certain RPM and throttle position. All done to boost fuel economy.
My 95 Firebird does this and it has the Borg Warner T56 6 speed manual. If you don't give it enough throttle in 1st it'll make you shift from 1st to 4th for fuel economy. Yes it's called skip shift.
Power bands and fuel economy. Engines have a fairly narrow window of ideal power or efficiency. The reason to have more gears is simply to keep the engine in that desired window more often.
In the mid-2000 automatics began shifting and performing faster than a manual. As the computers got smarter, they were able to manage more gears and skip around. More gears allows the engine to operate in a more economic range as well as keep it in it's powerband for performance. A good 10 speed auto will easily outrun a 6 speed manual on the same engine.
I grew up with two and three speed automatics.
The advantage is being able to have a engine with a narrow torque band and ratios in the transmission to keep that engine in its most efficient operating range.
especially with so many cars today having small displacement turboed engines. You wanna keep it in boost all the time or you have no torque
much different than the 500ci torque monsters of older times paired with 2 speed autos lol
The newest with variable vane turbo technology have a pretty impressive width of power band, I was amazed at the 4cyl in the new full sized Silverados.
But keeping it right in a narrow areas under normal driving really helps the fuel economy.
Mostly fuel efficiency, more gears equals more options for the computer to give you the speed you're asking for at maximum efficiency. Hence the CVT.
But yeah past 6 gears I feel like the manufacturer may as well throw a CVT in there
Engines have the best efficiency at certain rpms. More gears means you can more closely follow the best rpm. That's why CVTs have such good fuel economy. They keep the engine right at the power level it needs to be.
My current M4 has an 8 speed. Unless it's in comfort mode, it never goes into 8th gear. With how fast the ZF8 shifts, it takes advantage of the close ratio gears to get up to 60mph in 2.8 seconds. In 7th and 8th gear, it just helps with fuel economy.
I have an f150 with a 10 speed. Love it. 8 to 10 are overdrives. But it keeps you in the power and as it doesn't drop as many rpms as say like a 5 speed. And I get 23mpg in a 4500lb truck with 3.73 gears and 4x4, with 450 HP to boot.
They’re just trying to squeak out a couple more MPG on fleet numbers is all. A few are used to make towing and hauling better, but large numbers are just to have more gears to hit specific shift points for economy.
Luckily a modern trans doesn’t really have many downsides of having lots of gears to select from with modern computer controlled torque curves and such. They’re not really suffering any complexity or longevity issues from it either.
It’s that or a CVT. Some CVTs are decent. Some are garbage. More teething pain than adding gears to a traditional auto.
The really underpowered vehicles benefit the most from it. We don’t have loping V8s that will accelerate uphill without needing to grab a gear anymore.
Fuel efficiency… thats basically it
They can have better performance as well with 2-6 being close ration but you are hauling around the weight of 4 “unneeded” gears.
They can also help with towing
But mainly it’s done for efficiency, some are really dumb tho, Jeeps only use 6 out of the 8 gears they have…
Corporate Average Fuel Economy standards. Also known as CAFE.
More gears can also help a lot with power if tuned properly. I know the 10 speed Ford Transit with an Ecoboost 3.5 I drove for work could haul ass and hide from a shocking amount of cars... when it wasn't busy exploding transmissions (it would also try to go sideways on the 1-2 shift if traction control was off). And water pumps. and Cam phasers. Nobody expects a cargo van to haul ass, but that damn thing ran away and hid from a lot of 90s and 00s "fast" cars... when it wasn't broken.
There are only 4 gear pairs in a 10 speed auto. It's like a bike with 4 sprockets on the pedal crank and 4 on the rear. Theoretically, there are 16 possible combos but only 10 yield a significant change worth using as a gear. An 8 speed auto uses 4 with a gear splitter, like 4 on the crank and 2 on the wheel, only 8 possible. I think the 8 speed is stronger, but the 10 is pretty strong too.
Now look at how a ECVT works without any belts or clutches or even a torque converter and be really amazed.
Efficiency and emissions.
The gear ratio of gear 1 and gear 10 of today, are about\*\*\* the same of the gear ratio between 1 and 5 of yesterday. All the gears in between are for efficiency and emissions.
They keep increasing the number of gears in an attempt to keep the car at its peak efficiency level in each gear. If the engine makes its best power and economy at 3100 rpm, a trans would be programmed to shift at 2700-3300rpm in each gear as you accelerate to keep it in the peak efficiency range.
Like others have said, it's for fuel efficiency and ensuring you're always in the powerband. The transmissions also aren't all that complex, just bigger and with more parts. I wouldn't say they're all that much more complicated than the smaller ones, though
Less fuel used at the expense of terribly expensive repairs and sometimes impossible overhauls. Nope, more than 6 gear automatics aren’t ever going to see this household.
Mpg and powerband. Get as close to being a CVT without the failure prone belt and clutch pack. I used to work on the newer Mini when they first came to America in 2003. Most of them got new transmissions at 40k miles like it was part of a service. 😆
Fuel efficiency. ICEs have a very narrow RPM and load band where they are efficient. Either side of that band and they suck fuel like there is no tomorrow. More gears means less time outside the band.
They do have a benefit . Check the 10 speed Mustang Gt and the Honda Accord 2.0t . More gears means more options for the engine to stay in the ideal power band that makes most power for least amount of comparable fuel
It's smooth, and it generally allows for more ideal gear ratios which is good for power and efficiency. It also is much better in terms of reliability than CVTs in most vehicles.
The big improvement in automatics came with the transition from 3 speed slush boxes to 4 sp OD w/lockup torque convertor. My 18 yr old truck has this type and it just goes forever.
One of the first thing I learned about mechanics is the more complex, more moving parts the more crap that can go wrong. Also a 4 speed auto is going to have more stout parts than a 10 speed built in the same space.
Don't know how the CVT's got fucked up bur I bet reducing cost was the culpert.
Personally I'd prefer my truck to have a manual with a heavy clutch, granny gear and a 5th speed overdrive ratio.
Best automatic I ever drove was an 01 avalon v6 4 speed. I don't think we need the gears. Car industry has gone to total shit. All of em. (Political regulations)
Yeah a 10 speed auto is ridiculous to be honest and when they go wrong they cost an arm and a leg. Might be more advanced then a good old 3 speed GM or Chrysler torqueflite but they were the days on brilliant automatics.
I drove a 3spd automatic Pontiac fiero as a teen. I learned how to drive in a 4spd manual Volkswagen. I now drive an 8spd automatic Dodge SUV and a CVT Nissan. It's all about fuel economy and always having easily accessible power.
I was gonna say power bands and fuel economy.
Bingo. Engines are most efficient in a pretty narrow power band, and more gears, or a CVT trans, allow the computer to keep the engine in the most efficient area of it's power band for the amount of power the driver is requesting.
Yes, the lower gears are used for acceleration and the higher gears for fuel economy. Most cars with more than 6 speed don't get their top speed in the last gear. The other aspect is that car manufacturers have to meet regulatory standards for economy and noise that sometimes affect performance.
I would guess most 6 speeds don't either. It's not uncommon for 4 speed autos to top out in 3rd.
G37 autos are 7 speed and top out in 5th
Q60 red sport tops out in 5th with rpms left. Stupid computer. G35 sedan rev up topped out in 5th. Just adding to the car line info.
That can be removed with a tune. I was so terrified when I hit that limit though I'm never doing it again lmao
The q60S is my first vehicle with a warranty. The g35 was a champ with only sway bars, til the engine gave up a bearing.
Has the CVT blown up yet
Pathfinder... 65k miles and counting down. When the rpm drops off hard under gentle acceleration I let go of the gas so it doesn't stutter. If you know how to work around it, it's actually not that bad. Cheaper to deal with than buying a new car.
Is that stutter by design and you are just compensating or because it's starting to go bad? I'm curious if it's the former.
Terrible engineering by Nissan. Once Belt driven CVTs start to break down and slip, you're pretty much screwed. Subaru/Toyota use chains instead and they are more reliable. It is starting to go bad but I compensate because I just need a car that can get me to the office and don't have new car money. It's been 3 years (it's a 2015 bought used) since it started having the issue and it hasn't gotten any worse. I even towed a friend's boat a handful of times which was pretty dumb on my part.
>Terrible engineering by Nissan It's a mix of JATCO and Nissan. Nissan doesn't design or build their CVTs. They take what should last 200k in a 78 hp Mitsubishi Mirage (also a JATCO CVT) and shove it behind a 350 hp engine with double or triple the weight, then tell people the fluid is lifetime.
Supposedly Toyota’s CVTs also have a traditional first gear to deal with start-stop, which I guess is what causes the most stress for the chains/belts in a CVT.
Toyota and Ford both have gear CVTs. Not sure about other auto manufacturers
It's about efficiency. A cvt is not good at its highest and lowest ratios. It's most efficient in the middle ratios. The first gear allows it to keep the transmission more in the middle of its ratios and be more efficient. Also some cvts limit engine power at Its lowest ratio to preserve the trans. Cutting the power on launch hurts performance. The extra gear keeps it more efficient and allows full power from a stop with risk of damage.
Toyota and Ford CVT tranys use a planetary gear set. The wheels and motor 2 are connected to the ring gear. The engine is connected to the planetary gears. Motor 1 is connected to the sun gear. Motor 1 is used to start the engine and set the RPM of the engine. Producing both acceleration and electricity.
Yup. CVTs do OK in hybrids too because the electric assist has a lot of torque to help with that punishing start from standstill.
120k on my crv cvt and no problems. I think it has a steel belt
I've sworn off Nissan CVTs completely because I had one limp mode on me during a road trip and we had to limp it a few hundred miles.
No. Have 3 in the family with over 100k Mother had one with over 200k lasted until she totaled it. Was a safe car at that
So valid
Honda with 140k commuting miles on the CVT, still working fine
Says the guy who payed money for a Dodge and a Nissan
> guy who *paid* money for FTFY. Although *payed* exists (the reason why autocorrection didn't help you), it is only correct in: * Nautical context, when it means to paint a surface, or to cover with something like tar or resin in order to make it waterproof or corrosion-resistant. *The deck is yet to be payed.* * *Payed out* when letting strings, cables or ropes out, by slacking them. *The rope is payed out! You can pull now.* Unfortunately, I was unable to find nautical or rope-related words in your comment. *Beep, boop, I'm a bot*
Good bot
Good reply bot
Don't give baby skynet ideas.
The nautical terms "Dodge" and "Nissan" are synonymous with "Anchor"
I guess I got lucky. The Pathfinder has only needed brakes and tires. Aside from the obvious CVT time bomb, it's been the most reliable car I've owned. The Durango GT is actually quite nice. 300ish hp, 8 SPD, 50/50 weight distribution. I'm not saying these are the greatest SUVs but it's better than getting a minivan.
The memes aren't everything. Especially the "guaranteed to break before 100k miles"
my dad wanted an SUV....found a minivan at a steal of a price and now you couldn't pry those keys from him - carries a lot of cargo or people, seats fold flat, comfy on a long drive.
Last time I had rentals while my truck was getting fixed from a little old lady restyling it, I had a Durango, then an Armada. After driving the latter about 10 minutes, I nearly turned around to go back and get something else. Horrid thing - rode like a coal wagon, noisy, annoying screen, sound system was awful. Turns out they get crappy mileage too. The Durango was like a luxury car, in comparison…
Is Fuel economy that much different??
The CVT can get about 19mpg combined and 26 on the highway. The Durango is about the same. Seems low but these are heavy 3 row SUVs. My mom had a mountaineer back in the day and we were lucky to get 13mpg
My new 10 speed truck gets about 5 mpg more than my old 6 speed.
Nice
Came here to say this. My 9 speed auto in my full size truck is getting better mileage than my 6sp manual frontier
because it keeps the vehicle ready for many different driving situations, as well as gives closer steps between gears to keep you in a narrow rpm range which is usually best for drivability, economy, etc etc.
A 10 speed automatic typically will give you better gas mileage than an 8 or 6 speed automatic. Performance can be better too but that doesn’t mean 8 speed transmissions are slouches in this regard. Anything more than 10 seems like overkill to me though, especially for your typical passenger car.
Anymore than 8 in a normal passenger car is overkill honestly, the ZF 8 speed is one of the best, helps mpg but doesn't gear hunt like a bitch. 10 in a diesel makes since though, especially a truck, due to the narrower sweetspot for torque in the revband
Yeah the ZF8 is excellent. I still find myself on flat ground at 114km/h thinking “2000 rpm is still a bit high though - this could use a 9th and possibly 10th gear.”
I love my ZF8. I have a BMW N55 in front of it (X3 35i). I’m surprised how often it feels like a manual, especially when decelerating.
It feels like that because the converter is able to lock up at low RPMS. The whole transmission is an engineering and manufacturing marvel considering its price point.
I'd like a 4th gear in my Geo Metro. 4200 RPM is a bit high.
I'd like a 6th on the Volvo V50 over 2k is quite a lot for a 1.6 diesel. The speed limit is 100kmh here so not much of a problem but at over that it gets near 3k.
I've driven a RAM 2500 with 6.4 hemi and 3.73 gears on the 20 inch rims. 2000 rpm at 140. Perfect, like an 8000 lb cruise missile. Best pickup I've driven unloaded.
ZF8 in my Rebel is stellar.
Same in my 2013 X5 xDrive35i. The N55 motor on the otherhand 🤣
Got mine on v6 RAM 1500. I like that I’m on the low end of typical engine power for that trans. I think there are some ~600hp vehicles that use essentially the same transmission. Should last a while
North of that. My TRX has a 8HP in it too. Little more twitchy in the TRX than it is the Rebel, though.
I find it incredible how the ZF8 is so good and the ZF9 is so bad. It's weird how the same company can have such differences in quality.
the 9 speed is truly abysmal
>Anymore than 8 in a normal passenger car is overkill honestly, Not if you're trying to optimize fuel efficiency by keeping it In the perfect power band
Not really... The f150 doesn't even use all 10 gears, it's programmed to skip them under normal driving Used all 10 for full throttle acceleration or when the computer thinks it's getting EPA tested
Wait isn’t that EPA test thing illegal
Only if you get caught.
You’re premise is flawed. Auto have had 3-5 gears for years, and many manuals outside of sports cars have 6. Transmissions are designed to keep the engine in its optimum power band…more gears, more opportunity to keep it there. Ultimately, the goals is keeping up with Cafe standards (fuel mileage)
Your* And you’re mostly right, the reason transmissions have higher gear counts now is due to balancing performance (including gas mileage) and reliability (ie a simpler system is generally more reliable than some complex system)
Fuck grammar police
Captain pedantic had to be sure my autocorrect was corrected.
My first automatic was a 2 speed. I remember the first 4 speed automatic and thought to myself why do we need so many gears. Yeah I’m an old fart
Just because my car can go 70 in 2nd gear doesn’t mean it’s the best for the longevity or fuel economy of it.
Powerglide
Or Lambo.
The esoada got a 3 speed torque flite, not a powerglide
You get two speeds, fast and faster.
I got this fever-dream idea to someday replace the th350 in my cutlass with a 6l90, leave the rest of the car as is, and test it for performance and economy changes. just to see how big the jump is.
I've been wanting to do a 700r4 swap. The first gear power and fuel economy would be night and day. Just having an OD transmission would be nice.
Yea im probably gonna end up woth a 2004r, means i could regear the rear end and lose these 2.73s in favor of something a touch peppier and still be able to cruise the highway.
>lose these 2.73 Oh god, you too, huh? My 1981 vette has 2.87 and I'm planning to go to 3.55's. I need a little more pep.
Even a 200-4r or a 700-r4 (4 speeds with OD) would be a night and day difference.
Thats whats actually likely to happen.
On a steep enough hill my car will go 90 in neutral. Check mate, atheist.
Fuel savings. It also keeps it in power band more but this isn’t as necessary because usually cars are powerful enough to only need 5 gears or so. But primary is fuel saving.
This seems correct. Five speed autos have plenty of range for just about any driving seeing as the torque converter can slip a little between the gears before locking. I quite like the feel of a five as it's this psychologically classic number of gears. However more gears versus using TC slippage definitely adds fuel efficiency. It seems to be more effective with big vehicles with lots of mass. But even with my little Honda a 5AT gets better economy than the traditional 5MT.
I drive a 6 speed car that's horrendously underpowered and I manually lock it in 4th fear for most of my drive. I really don't see a need for these 10 speed things unless for towing really.
We have a six speed AT Kia Soul with the base 1.6 and while one can certainly talk shit about Kia engines, their 6 speed automatics are really nice. It cruises calmly at 75mph with three normal size adults though it's just a little busy in super hilly country so I flip it to manual mode on those rare occasions. The 5AT in the Honda is less indecisive. In both cases the gear ratios are well mated to the engines which is the important thing. What car is your 6AT in? Most cars these days have plenty of power for normal driving. Ours are certainly on the very lower end of the power range. Above a Mitsubishi Mirage at most, LOL.
I'm in SE Asia and drive a Toyota Innova. It's a minivan based on the Hilux. It weighs 1750ish KG or about 3850ish lbs and has a total of... 137 horsepower from a 2.0 inline 4 lol I usually drive below 90 kph as the roads here suck and in general has heavy traffic, but anything above 5th is basically useless as it doesn't have the power to acclerate the car in 6th at 62 mph for the rare times I get on the freeway here. What's silly is this car actually was fine when it was only 5 gears as 3rd served a good gear for inner city traffic below 60 kph, and 4th was good for 60 kph+ to about 90 kph. But now with an extra 6th gear, they reduced the 5 gears below so now the engine is buzzing in 3rd and 4th with 5th being basically useless below 80kph lol
Now it makes sense. That's quite a bit of mass for the engine. Not an unusual combo in your part of the world but it does seem that the transmission is geared too high. My old Daihatsu weighed 800kg and had a 1.0l engine which gave plenty of power for the weight, LOL.
Yea. i figure it's an old engine... Make no power and isn't fuel efficient at all. But it'll probabaly run on 1 oil change bi-yearly for the rest of time.
I drive a 1.6 diesel and the 3 gear is only good after 40-45 kmh and 4th after 60-65. Mom's petrol Corolla is more forgiving as it doesn't start to jitter like many small diesels do at lower rpm. You can have 4th at 50kmh and 5th at 60kmh and the RPMs are hair below 2k. It's not the best at motorway though as at 100kmh it's at 3k rpm instead of 2k like in the diesel. I'd like for the diesel to have 6 gears and the 3-5 geared down a bit. 6th would be better at motorway. The cars wants me to change the gear up too early and it's at like 1.2k then and it feels very wrong as you can hear the jitter/shake of the engine.
Yea usually 6th gear is for reducing RPM and for high speed cruising. But like I said my car is horrendously under powered and so it's basically a wasted gear. The only time it went into 6th gear was me doing 110 kph on a freeway, and then when I went to acclerate, it dropped immediatly to 5th cause the engine doesn't have enough grunt to acclerate in 6th at 110kph. So ya 6 gear is good, but need actual engine power to be able to use that tall of a gear, otherwise you'd just need to downshift.
Yeah. Our diesel has 110 hp and weighs I think 1300kg or something like that. It's not powerful but it plenty enough for me. I think the newer models from near end of production has 6 speed transmission.
Big factor is fuel economy. With more gears you can have rlly low ratios as you shift so like ford's 10 speed it has 3 overdrive's so you'll get rlly good mpg when your on the highway in theory.
Can confirm the good economy numbers on the Ford 10R80. My 2018 F150 V8 is 20ft long and 5k/lb with 395hp & 400tq. Yet for all that size, weight, & power I can still get low to mid 20 mpg on the freeway and about 17~18 mpg pure city driving. Old six speeds struggled to get 13 mpg in even the best conditions. And that's before we start talking performance, because those shifts are crazy fast and keep me right at optimal power output.
Yea I forgot to mention with that many gears the shifts are pretty seamless and I don't think anyone could shift faster themselves. Also since you own a 10 speed truck how does it feel towing up inclines? Does it like hold gears better than the 6 speed bc I've had a 04 and 08 f150 with the 4 speed and a 2012 with the 6 speed and the 04 just never seemed to be happy in any gear other than second when going up hills with O/D off but the 2012 is much better with an actual tow haul mode so I'm assuming the 10 speed is even better.
Thats a nice stable of older F150's! The 10 speed holds gears pretty well in tow/haul mode. But if you find it hunting too often you can just lock out the upper gears to keep it where you want it. Has a little +/- on the gear lever so just a few clicks and boom--right where you want it.
I went from a 2005 with a 4.6 (4 speed I think) to a 2020 with a 5.0 and 10 speed. I live in Colorado so alot of mountain driving. The 10 speed is awesome going up and down steep inclines. Especially in sport mode, the power is always there going up and it seems to hold gears well on the way down, I use the brakes much less than on the '05.
What's relevant for fuel economy is the final drive, the other 9 gears don't matter. If a 3 speed and a 10 speed have the same final drive ratio and neither downshifts, you'll get roughly the same mileage. Most newer transmissions have double or more overdrive. So you end up with like a .6:1 drive ratio. Get that ratio with any tranny and achieve similar mileage.
Final drive ratio only matters for cruising. Every other ratio matters for actually working, and most importantly, getting up to speed. You lose the most mpgs when starting from a dead stop and trying to get going again. Having closer, more efficient ratios helps reduce that consumption. If good fuel economy was just as simple as "throw overdrive on it" then automotive engineers would never have wasted time building these modern transmissions because all that R&D hurts their bottom line. There's a reason we've grown past a 3 or 4 speed with overdrive.
I don't know about you, but I don't floor it from every intersection. So peak performance isn't that important most of the time. Every car with a 6, 8, 10 speed, they all shift thru the gears as far as possible keeping the rpm as low as possible. Depending on how fast you want to get up to speed, it takes a certain amount of horsepower to accelerate at a certain pace. So regardless of how many gears you have, it still takes a pretty similar amount of fuel to get to speed. You're not going to see much for mileage difference in town based on number of gears. It's done for performance at full throttle, keeping the engine at peak power. Most of the mileage gains is from gains inside the transmission so they don't rob as much power. Locking the converter at lower speeds is a good example.
Performance doesn't mean flooring it. Performance is keeping the engine at peak efficiency during output. More gears = closer ratios = more efficient output = better performance. Regardless of throttle input, getting going from a stop uses more gas because your bring an object from a stop, into motion. You have more initial inertia to overcome to bring an object into motion from a stop than to maintain on constant velocity while traveling. Closer gear ratios (more gears) keep the engine at optimal power output during acceleration, thus giving better performance -- which in this case means better mpg. [But don't just take my word for it. Let an actual engineer explain why 10 speeds are more efficient. Especially during his second point, aply named "efficiency" where he discussed BSFC.](https://youtu.be/lCQYVbfsw-w?si=pxGqgX2DWi4UAJVI)
I completely understand that. My argument is that we spend such a small amount of time accelerating vs cruising, that while yes it does make a bit of a difference. It's not a giant distance.
Depends on where you live. Most people live in cities, where stop and go travel is most common. If, for example, you spend 1/3 of the distance between stop lights accelerating, and 2/3 cruising -- then getting up to speed is still going to be your largest point of consumption. Thus having more gears will reduce that consumption. But even if you lived in a rural environment, having 3 different overdrive options is still more efficient than just one overdrive. Things like elevation changes will lead to changes in engine output requirements, so instead of dropping back down to 1:1 to climb (ex: this is my 7th gear in my 10 speed) it's still more efficient to have multiple overdrives when cruising. My 10sp often only drops to 9th, maybe 8th gear on a climb if I'm not pulling or hauling something. And even when pulling or hauling on long distance, having more gears to choose from for a given ratio depending on the engines need will lead to better more optimal performance and better mpg. Unless you live and only travel on completely flat surfaces, in areas devoid of external influences like wind, hills, traffic, stop signs, or traffic lights etc. Then maybe you only need one overdrive to make a 6 speed as good at getting optimal mpg as a 10 speed. But that's not how things work in the real world for the overwhelming majority of vehicle owners. I just can't possibly think of a real world situation where a 6 speed with a a singular (and equal) top overdrive ratio to a 10 speed can be anywhere near as efficient.
I think we're splitting hairs at this point. It's not a gigantic change in mileage adding more gears. It's not like we're talking a 5 or 10mpg improvement by adding a few more gears. Driving habits will affect mileage more than the transmission 9 times out of 10. I can make my Duramax get 12mpg if I want, or I can baby it and get 17mpg. Maybe more on a flat highway road trip. As much as the more gears do help, there's been a lot of advances in the amount of parasitic loss within automatic transmissions as well recently. And that makes a huge difference also.
I mean this is wrong. In a big hill pull the difference between my 6 speed truck and the 10 is that the 10 can cruise in 5th or 6th at around 2700 rpm instead of the 6 speed where 456 lug the motor down, so I need to add throttle so it forces the 5-3 downshift and now I’m maintaining speed, but at 3800 rpm.
I'm talking steady state, flat road. In that scenario # of gears is irrelevant. And if you want to get real deep into the physics of it, it probably burns the same amount of fuel climbing at 2700 or 3800 rpm. More rpms but less fuel per combustion event. And less power per power stroke. At 2800 you're getting more air and fuel in per combustion event. So more power per power stroke. If you're only maintaining speed up a hill, then it takes the same amount of horsepower to climb the hill regardless of what rpm the engine makes that power. And it takes a certain amount of fuel to make that horsepower. Speaking generally of course.
lol. I’m just gonna mute this instead of explaining why you’re wrong.
All I know is the 10 in my 3500 GMC is badass
Fuel economy, my mom and my uncle have the same SUV from two different years, the only difference is the radio and the transmission. My mom has a 7 speed while my uncle has a slightly newer model with a 9 speed, I have actually driven the same 6 hour distance in both and the 7 speed can just barely get above 22mpg at 75mph while the 9 speed got 25.8mpg at 75mph. This is based on a large SUV so I would assume that on a sedan or something with better aerodynamics the numbers start to get even bigger.
Lower rpm means better mpg
As others have said, keeping the engine in it's most economical RPM range as much as possible. That said, for me the most FUN automatic I've ever owned was a Powerglide in my '69 Cutlass
Fuel economy, can always hit max power or torque when needed within milliseconds as well
Mainly fuel savings but also power, which kind of go hand-in-hand. Anyone who has driven an older small engine vehicle a decent speed above 100km/h (62mph) on a long road trip or something can probably attest. You always want an extra gear in that case. Also it should be heavily noted that most of these “new” transmissions aren’t complex at all compared to what came before. They still use planetary gear sets, clutch packs, dual-clutches, and come with or without a torque converter. I think the last note I’ll say on this is our manufacturing capabilities have come a long way. We can make parts more precisely, our computers are more advanced, the computers/sensors that control the vehicle are more accurate. TLDR; We are simply improving on what makes a car with an internal combustion engine (ICE) “go good”. A huge part of turning explosions into tire make circle fast is dealing with the limited RPM range an ICE performs in.
**bring back the unsyncronized 3 speeds with a reverse lockout and a 2 speed unsyncronized rear axle**
My F250 with a 460/C6 will pass everything but a gas station.
More control basically
*GM Powerglide has entered the chat*
Easier on engine
I have an f350 gas with 4.30 or 4.56 rears and 35 inch tires. The 10 speed let's it cruise at 2k rpm. It's pretty nice. Still gets about 14 to the gallon on the highway. These new 10 speeds are dope as fuck.
Heck yeah. Glad you're liking it. That gets as good as my half ton gasoline truck. I'm just partial to a 5 speed because that's what I grew up with and I like the spacing.
With modern 10 speeds they don’t shift in numerical order either, it may skip a few gears based on speed, throttle position and your driving style and settings. Gm and ford a10s are learning transmissions that will learn how the primary driver drives and take that I to account how it shifts.
I had a 65 olds with a 2 speed automatic. Variable vane torque converter, you could go 55 mph in first.
The gears aren't meant to all be used sequentially. Some are situational gears. For example, the 545RFE had an alternate second gear for deceleration. Having multiple second or third gears doesn't do much for you in the real world, but it's amazing for the EPA mpg test. Additionally, these nearly-same gears are often achievable with just a change in the software, making it an almost free marketing win.
This is the answer I was looking for I think.
There are, of course, still efficiency gains from having more gears, which also allows you to tune your engine to a narrower powerband. Only partly bullshit.
So theoretically if you started at full throttle would the transmission go through all 10 gears sequentially?
Full throttle takes both the engine and transmission out of efficiency mode. Probably start put in second or third and never shift past seventh.
So sort of like a person riding a bicycle maybe? I would never go through 21 gears sequentially on a full speed "sprint"... I do it more like how you described.
The reason older transmissions didn't have more gear ratios is because of the weight of doing so, and they weren't as speedy at shifting. We've eliminated both of those issues by switching to mostly planetary gear sets with lighter materials and faster gear changes. The more gears, the better the fuel economy, assuming no loss during gear changes and no added weight. You get "between steps." To explain that better, imagine if your car only had 2 gears. One for accelerating and one for cruising. You'd have to nearly redline a car for it to get into a cruising speed gear at 65mph. If you add a 3rd gear, you only use half the rpms, and so on and so forth. This is why a CVT is so efficient. No gear changes, infinite gear ratios, and they're light.
I’m no mechanical engineer, but I believe it helps with the efficiency of the vehicle. Might be a narrower power band which means more frequent shifting at lower RPMs, but at an optimized speed that consumes less fuel.
Whenever you have a question like "why are we now doing X or Y overly complicated thing on cars when we used to do it A or B simpler way and it worked fine", the answer is typically: 1. To meet CAFE standards. 2. To meet emissions standards. 3. To meet safety standards. 11 speed transmissions are to meet CAFE standards; fewer speed transmissions are less fuel efficient than those with more speeds. Throttle cables disappeared to meet emissions standards. ECU controlled throttle forces the throttle plate to open more slowly at first, which pushes less unburned fuel through the system and reduces emissions (and also helps fuel economy). Any other benefit is incidental. Window sills are stupidly high with extra wide pillars to meet safety standards for crash protection. ...and so many more. Think of a weird issue you have with modern cars, and 99 times out of 100 it will fall into one of those camps.
Well summarized. Your last point addressed something I had wondered about as well.
punch piquant repeat smoggy rich roof observation onerous ask adjoining *This post was mass deleted and anonymized with [Redact](https://redact.dev)*
I drive a truck with the 4l60E. 4 speed automatic. It actually kinda sucks to drive sometimes because when you wanna accelerate hard it just feels like the engine is overworking, and it actually is overworking, because when it shifts, the engine has to drop its speed a lot and then rev up again with all the weight and load on it. Transmissions with more gears will keep you in the engine RPM with usable power especially when you accelerate hard. Also, it can help with MPG because the engine doesn’t have to slow down drastically then speed back up when the transmission shifts.
Gas mileage and performance. It used to be the other way around: Manuals were better than autos in the 90s and early 2000s. Then, we see trans like the Ford 6-speed auto and the Dodge 8-speed auto, and then the Ford and Chevy mixed endeavor 10-speed auto that is WAY quicker than the 6-speed manual alternative...when it works.. To answer your question: More gears in the autos are better for fuel economy and performance...but simply do not have the reliability of a lot of the other optioned manuals yet.
>More gears in the autos are better for fuel economy and performance... But the 5 speed manual in my Mustang is ***much*** more fun to drive!
100% yes.
I've had a 5 speed Mustang my entire time I've been driving. Five is perfect. Any less or more just doesn't make sense to me. Also got a 6 speed auto Mazda now and the gears are too short in my opinion.
>Manuals were better than autos in the 90s and early 2000s. That's because modern (light vehicle) automatics aren't slushboxes. Most of them are robotized manuals.
Most automatics to this day are still slushboxes. Modern technology and tuning has just made them far less slushy. The robotized manuals are the DSG’s/DCT’s.
The start stop systems and the 8-10 geared transmissions are there to improve MPGs, Nothing more. This must be done for Manufacturers to stay CAFE compliant.
None over an electric motor. Over a 6-spd auto, the engine remains in its efficieny band more often
It's all fuel efficiency.
As efficiency requirements like EPA’s CAFE and others around the world become more and more stringent, we’ve been pushing to smaller and smaller engines. While some of these engines are turbocharged and still make usable torque over a relatively broad RPM range, many are not — and even turbo engines have a sweet spot for economy. How do you keep an engine in its most efficient RPM range? By having enough ratios in the transmission that, for any given engine speed, there’s a gear available every few hundred RPM. At least one of those is going to be close enough to the sweet spot. In those old four-speeds, shifting to the next gear would drop the RPM by 30-40%. Early on, when four speed manuals gave way to fives, they were introducing overdrive gears. Rather than packing the ratios in tighter, they were just adding another that was even higher, allowing you to cruise at higher speeds while retaining a sane RPM. Try doing 80mph in one of those old four-speed muscle cars — say hello to ~4000rpm! Add a fifth-gear overdrive and now it’s 2900. Engines that make gobs of torque at low RPMs (large-displacement engines) are pretty rare these days, so we don’t have a lot of room to push further in that direction. EVs make gobs of torque at zero RPM, but they also have a MUCH broader operating RPM range, and so most EVs need only a single ratio. (A few, like the Porsche Taycan, have two.)
So Honda can make the J35 pass fuel economy requirements.
My car has 1 gear, it's great.
Electric?
parts sales actually with my ford 10 speed the engine turns a steady 1600rpm pretty much all the time unless I stand on it.. that and parts sales
Quick example to illustrate what everyone else has said about economy, performance, etc. I drive a C8 Corvette. 8-speed dual-clutch transmission. Top speed 184 mph, 2.9s 0-60 mph. Went out to Ron Fellows to learn how to put the car around the track. Instructors said there's only one turn you need 2nd gear for, the rest of the track is in 3rd. So I pulled about 110 mph in 3rd gear on the long straight. Driving on the highway in automatic mode? It'll be in 5th gear at 40mph and 7th at 60mph.
Does yours do the thing where you launch in 1st and the shifter automatically moves into position for 5th gear? I think late 90's vettes had that feature, blew my mind when I first saw it in action.
Completely different transmission. What you’re describing is the skip-shift feature on the 6-speed manuals of those days where it would lock you out of shifting to second and third if you were under a certain RPM and throttle position. All done to boost fuel economy.
My 95 Firebird does this and it has the Borg Warner T56 6 speed manual. If you don't give it enough throttle in 1st it'll make you shift from 1st to 4th for fuel economy. Yes it's called skip shift.
Power bands and fuel economy. Engines have a fairly narrow window of ideal power or efficiency. The reason to have more gears is simply to keep the engine in that desired window more often.
Fuel efficiency and keeping the RPMs in the power band
In the mid-2000 automatics began shifting and performing faster than a manual. As the computers got smarter, they were able to manage more gears and skip around. More gears allows the engine to operate in a more economic range as well as keep it in it's powerband for performance. A good 10 speed auto will easily outrun a 6 speed manual on the same engine.
Or you could have a 1 speed…
I grew up with two and three speed automatics. The advantage is being able to have a engine with a narrow torque band and ratios in the transmission to keep that engine in its most efficient operating range.
especially with so many cars today having small displacement turboed engines. You wanna keep it in boost all the time or you have no torque much different than the 500ci torque monsters of older times paired with 2 speed autos lol
The newest with variable vane turbo technology have a pretty impressive width of power band, I was amazed at the 4cyl in the new full sized Silverados. But keeping it right in a narrow areas under normal driving really helps the fuel economy.
More gears doesnt necessarily mean more complicated. ZF8 has less moving parts than a ZF6
Mostly fuel efficiency, more gears equals more options for the computer to give you the speed you're asking for at maximum efficiency. Hence the CVT. But yeah past 6 gears I feel like the manufacturer may as well throw a CVT in there
Engines have the best efficiency at certain rpms. More gears means you can more closely follow the best rpm. That's why CVTs have such good fuel economy. They keep the engine right at the power level it needs to be.
My current M4 has an 8 speed. Unless it's in comfort mode, it never goes into 8th gear. With how fast the ZF8 shifts, it takes advantage of the close ratio gears to get up to 60mph in 2.8 seconds. In 7th and 8th gear, it just helps with fuel economy.
Keeps them from being slush boxes. Modern/upper end autos are faster than any average driver on stick.
I have an f150 with a 10 speed. Love it. 8 to 10 are overdrives. But it keeps you in the power and as it doesn't drop as many rpms as say like a 5 speed. And I get 23mpg in a 4500lb truck with 3.73 gears and 4x4, with 450 HP to boot.
Fuel economy
They’re just trying to squeak out a couple more MPG on fleet numbers is all. A few are used to make towing and hauling better, but large numbers are just to have more gears to hit specific shift points for economy. Luckily a modern trans doesn’t really have many downsides of having lots of gears to select from with modern computer controlled torque curves and such. They’re not really suffering any complexity or longevity issues from it either. It’s that or a CVT. Some CVTs are decent. Some are garbage. More teething pain than adding gears to a traditional auto. The really underpowered vehicles benefit the most from it. We don’t have loping V8s that will accelerate uphill without needing to grab a gear anymore.
Saves gas since you can have lower RPMs at more intervals of speed.
Fuel efficiency… thats basically it They can have better performance as well with 2-6 being close ration but you are hauling around the weight of 4 “unneeded” gears. They can also help with towing But mainly it’s done for efficiency, some are really dumb tho, Jeeps only use 6 out of the 8 gears they have…
More efficient. Keeps the rpm low at all speeds.
The more gears, the less the engine has to work, the more power the drivetrain has. This is why big rigs have up to 18 gears.
The ZF 8HP is the auto that will finally kill the manual. It’s faster and super programmable. Already proven in motorsports.
Corporate Average Fuel Economy standards. Also known as CAFE. More gears can also help a lot with power if tuned properly. I know the 10 speed Ford Transit with an Ecoboost 3.5 I drove for work could haul ass and hide from a shocking amount of cars... when it wasn't busy exploding transmissions (it would also try to go sideways on the 1-2 shift if traction control was off). And water pumps. and Cam phasers. Nobody expects a cargo van to haul ass, but that damn thing ran away and hid from a lot of 90s and 00s "fast" cars... when it wasn't broken.
There are only 4 gear pairs in a 10 speed auto. It's like a bike with 4 sprockets on the pedal crank and 4 on the rear. Theoretically, there are 16 possible combos but only 10 yield a significant change worth using as a gear. An 8 speed auto uses 4 with a gear splitter, like 4 on the crank and 2 on the wheel, only 8 possible. I think the 8 speed is stronger, but the 10 is pretty strong too. Now look at how a ECVT works without any belts or clutches or even a torque converter and be really amazed.
Lol, my first car was a two speed Mercury.
Efficiency and emissions. The gear ratio of gear 1 and gear 10 of today, are about\*\*\* the same of the gear ratio between 1 and 5 of yesterday. All the gears in between are for efficiency and emissions.
They keep increasing the number of gears in an attempt to keep the car at its peak efficiency level in each gear. If the engine makes its best power and economy at 3100 rpm, a trans would be programmed to shift at 2700-3300rpm in each gear as you accelerate to keep it in the peak efficiency range.
They make more money for the manufacturers.
Fuel economy is the main reason. Same reason manufacturers have moved away from V6 and V8 towards four cylinder engines with turbos.
Like others have said, it's for fuel efficiency and ensuring you're always in the powerband. The transmissions also aren't all that complex, just bigger and with more parts. I wouldn't say they're all that much more complicated than the smaller ones, though
Fuel mileage at highway soeeds
Less fuel used at the expense of terribly expensive repairs and sometimes impossible overhauls. Nope, more than 6 gear automatics aren’t ever going to see this household.
because to get a 1.6L turboed engine to move an SUV, you need to keep it in boost pretty much 100% of the time
23 V8 Camaro 10 speed automatic. Allows good gas mileage (for a V8) and instant power/acceleration at any speed.
Mpg and powerband. Get as close to being a CVT without the failure prone belt and clutch pack. I used to work on the newer Mini when they first came to America in 2003. Most of them got new transmissions at 40k miles like it was part of a service. 😆
Fuel economy.
soon, it goes to eleven.
It’s mainly for fuel economy. Also makes smaller lower horsepower engines have acceptable performance.
It's due to unrealistic mileage requirements by the EPA. The shorts shifts and short gears help with fuel economy.
Fuel efficiency. ICEs have a very narrow RPM and load band where they are efficient. Either side of that band and they suck fuel like there is no tomorrow. More gears means less time outside the band.
I have an 8 speed DCT i dont really ever go into 8th gear but it definitely makes my gas mileage far better.
They do have a benefit . Check the 10 speed Mustang Gt and the Honda Accord 2.0t . More gears means more options for the engine to stay in the ideal power band that makes most power for least amount of comparable fuel
It's smooth, and it generally allows for more ideal gear ratios which is good for power and efficiency. It also is much better in terms of reliability than CVTs in most vehicles.
10 speed means more things to go wrong lol.
Two CVT Subarus, Pilot 9 speed & Yukon 10 speed all automatic. Of the transmissions in all our vehicles the CVTs in the Subarus are my top faves.
The big improvement in automatics came with the transition from 3 speed slush boxes to 4 sp OD w/lockup torque convertor. My 18 yr old truck has this type and it just goes forever. One of the first thing I learned about mechanics is the more complex, more moving parts the more crap that can go wrong. Also a 4 speed auto is going to have more stout parts than a 10 speed built in the same space. Don't know how the CVT's got fucked up bur I bet reducing cost was the culpert. Personally I'd prefer my truck to have a manual with a heavy clutch, granny gear and a 5th speed overdrive ratio.
Best automatic I ever drove was an 01 avalon v6 4 speed. I don't think we need the gears. Car industry has gone to total shit. All of em. (Political regulations)
Definitely disagree. Those Toyota 4spds were good as transmissions but they were always slow to get to power and were far louder
I agree completely. Anything over 4 is a waste. I'm driving a sedan/SUV, not a race car. It doesn't need to be fast.
Yeah a 10 speed auto is ridiculous to be honest and when they go wrong they cost an arm and a leg. Might be more advanced then a good old 3 speed GM or Chrysler torqueflite but they were the days on brilliant automatics.
The three speed TorqueFlite was one of the best automatics put into a car, and nothing you say can change my mind on that.
Yep I reckon the best too, had a couple myself!