Does gear shifting wear a transmission?

[coxmaster]

I have a related question that you guys might be able to answer.

I understand how and why clutches wear; so why is it that the dual clutch automatic transmissions have "lifetime" clutch packs? According to VW my clutches should never need replaced at any point in the cars lifetime and as far as I know the similar transmissions have the same idea. What is different about these vs a standard manual transmission clutch?

 

[JCH13]

I have a related question that you guys might be able to answer.

I understand how and why clutches wear; so why is it that the dual clutch automatic transmissions have "lifetime" clutch packs? According to VW my clutches should never need replaced at any point in the cars lifetime and as far as I know the similar transmissions have the same idea. What is different about these vs a standard manual transmission clutch?

I think it's for two main reasons:

1) The wear is spread between two clutches instead of one
2) The engagement and disengagement is closely controlled by a computer on the car, and not a person who might ride the clutch all day long, or slip it too much between shifts or on hill starts, or do other things to shorten the clutches' life.

 

[ShawnD1]

I understand how and why clutches wear; so why is it that the dual clutch automatic transmissions have "lifetime" clutch packs? According to VW my clutches should never need replaced at any point in the cars lifetime and as far as I know the similar transmissions have the same idea. What is different about these vs a standard manual transmission clutch?

Not really much of a difference in the clutch itself. Lots of manual transmissions will run for a decade before the clutch needs to be replaced, and sometimes it never needs to be replaced throughout the life of the car. As long as you're at least trying to match rpm when shifting, a manual clutch will last a long time. The bulk of the wear is done when starting the vehicle from a stand still, driving like a retard (resting your foot on the clutch even when you're not using it), and "power shifting" where you keep giving it gas while shifting instead of letting the rpm drop while shifting.

Clutches in an automatic transmission wear out a lot faster because the transmission will "power shift" every time. If you floor it and the thing is revving up to 6k then dropping to 4 while your foot is still hamming the gas, that right there was a power shift and it just put a lot of wear on the transmission. Even when you're just lightly touching the pedals, you're still touching the gas while it's shifting. That's why this thread exists; I want to know if low speed low power gear hunting will destroy the transmission or if the wear is negligible.

Your dual clutch system is more like a rev-matched manual. Two gears are always engaged and it switches from one to the other. There's no synchro time or synchro grinding. Your car will shift in 10 miliseconds and it has continuous power, but mine has a looooong upshift time and it's stressing the clutches that whole time.

 

[Sukhoi]

Not really much of a difference in the clutch itself. Lots of manual transmissions will run for a decade before the clutch needs to be replaced, and sometimes it never needs to be replaced throughout the life of the car. As long as you're at least trying to match rpm when shifting, a manual clutch will last a long time. The bulk of the wear is done when starting the vehicle from a stand still, driving like a retard (resting your foot on the clutch even when you're not using it), and "power shifting" where you keep giving it gas while shifting instead of letting the rpm drop while shifting.

Clutches in an automatic transmission wear out a lot faster because the transmission will "power shift" every time. If you floor it and the thing is revving up to 6k then dropping to 4 while your foot is still hamming the gas, that right there was a power shift and it just put a lot of wear on the transmission. Even when you're just lightly touching the pedals, you're still touching the gas while it's shifting. That's why this thread exists; I want to know if low speed low power gear hunting will destroy the transmission or if the wear is negligible.

Your dual clutch system is more like a rev-matched manual. Two gears are always engaged and it switches from one to the other. There's no synchro time or synchro grinding. Your car will shift in 10 miliseconds and it has continuous power, but mine has a looooong upshift time and it's stressing the clutches that whole time.

Are you saying clutches in an auto wear out faster than in a manual?

 

[jlee]

Not really much of a difference in the clutch itself. Lots of manual transmissions will run for a decade before the clutch needs to be replaced, and sometimes it never needs to be replaced throughout the life of the car. As long as you're at least trying to match rpm when shifting, a manual clutch will last a long time. The bulk of the wear is done when starting the vehicle from a stand still, driving like a retard (resting your foot on the clutch even when you're not using it), and "power shifting" where you keep giving it gas while shifting instead of letting the rpm drop while shifting.

Clutches in an automatic transmission wear out a lot faster because the transmission will "power shift" every time. If you floor it and the thing is revving up to 6k then dropping to 4 while your foot is still hamming the gas, that right there was a power shift and it just put a lot of wear on the transmission. Even when you're just lightly touching the pedals, you're still touching the gas while it's shifting. That's why this thread exists; I want to know if low speed low power gear hunting will destroy the transmission or if the wear is negligible.

Your dual clutch system is more like a rev-matched manual. Two gears are always engaged and it switches from one to the other. There's no synchro time or synchro grinding. Your car will shift in 10 miliseconds and it has continuous power, but mine has a looooong upshift time and it's stressing the clutches that whole time.

Are you aware that modern engines will do electronic wizardry (e.g. pull timing) during shifts to lessen the wear on the transmission? An auto trans will typically last quite a long time...I daresay longer than most people will own their cars.

 

[ShawnD1]

Are you saying clutches in an auto wear out faster than in a manual?

Yep. Most manual vehicles will never need to have the clutch replaced.

The one thing manual and auto have in common is that most of it depends on how you drive. Your grandma's automatic will last forever because she accelerates super slow. My auto transmission will be lucky if it lasts 5 years because every merge onto a highway or freeway is a pedal to the floor clutch burning extravaganza. Automatics really don't like being loaded down, which is basically what I'm doing when I'm flooring it. If you buy a van or suv and it has an optional towing package, that towing package likely includes an additional cooler for the automatic transmission.

 

[JCH13]

Yep. Most manual vehicles will never need to have the clutch replaced.

Quite possibly one of the silliest things you've ever guessed at. You'd really think that a person, with all of the associated control flaws, would wear out a single clutch SLOWER than a sophisticated computer-controlled transmission with 4-8 times as many clutches to wear out? Really?

 

[jlee]

Did someone just post a thread asking about automatic transmission wear...and then, in the space of the very same thread, suddenly become an expert on the subject?

:hmm:

 

[ShawnD1]

Quite possibly one of the silliest things you've ever guessed at. You'd really think that a person, with all of the associated control flaws, would wear out a single clutch SLOWER than a sophisticated computer-controlled transmission with 4-8 times as many clutches to wear out? Really?

I've had 2 manual transmission cars myself and neither of them ever needed clutch replacing. My friend's first car was still on its original clutch at 200,000 miles and it was starting to slip just before he sold it. If you're burning out the clutch, it means you either suck at driving or you're driving like a lunatic.

 

[kornphlake]

I think your logic is flawed, when you use the clutch in a manual you are using one clutch for every shift 1-5 plus reverse, in an auto you're using several clutches for each shift. I could argue that the clutches in an automatic will last longer because they're working 1/4 as often as the clutch in a manual and because the wear is spread out among several clutches.

In the real world all clutches are not equal, not all drive trains are equal, not all drivers are equal. It's unreasonable to say that one is going to last longer without some other qualifying statements.

 

[JCH13]

I've had 2 manual transmission cars myself and neither of them ever needed clutch replacing. My friend's first car was still on its original clutch at 200,000 miles and it was starting to slip just before he sold it. If you're burning out the clutch, it means you either suck at driving or you're driving like a lunatic.

And I've seen a thousand NYC cabs with 450,000+ miles on the original automatic transmission.

You realize, of course, that the clutches in an automatic transmission do not actually transmit torque, but rather fix or release different stages of a planetary gear set, right?

 

[ShawnD1]

Did someone just post a thread asking about automatic transmission wear...and then, in the space of the very same thread, suddenly become an expert on the subject?

:hmm:

I'm just like John Kerry. I win a bunch of medals, throw them out, lie and say I didn't throw them out, say I'm against militarism, then say I'm proud of my military service. It's a tough gig.:awe:

 

[ShawnD1]

And I've seen a thousand NYC cabs with 450,000+ miles on the original automatic transmission.

You realize, of course, that the clutches in an automatic transmission do not actually transmit torque, but rather fix or release different stages of a planetary gear set, right?

Clutch in a manual only wears when you're releasing it. Once the thing is in gear, there's no slip, no wear, no clutch damage of any kind.

 

[JCH13]

Clutch in a manual only wears when you're releasing it. Once the thing is in gear, there's no slip, no wear, no clutch damage of any kind.

Okay? What's your point?

 

[ShawnD1]

Okay? What's your point?

By stating that automatic transmission clutches do not transmit power, you are implying that transmitting power damages the clutch.

 

[Sukhoi]

Did someone just post a thread asking about automatic transmission wear...and then, in the space of the very same thread, suddenly become an expert on the subject?

:hmm:

In one day we have indeed gone from asking how gear shifts work in an auto, to declaring a heavily used auto will wear out in 5 years while a manual will last hundreds of thousands of miles.

 

[JCH13]

By stating that automatic transmission clutches do not transmit power, you are implying that transmitting power damages the clutch.

You assumed that is what I said, it is not. Not even close...

In an automatic transmission the clutches control what parts of a planetary gear set move, and what parts do not. They are only responsible for stopping the inertia of small pieces of metal and holding them in place.

In a manual transmission the clutch connects the engine's output to the transmission and slips until the engine and wheels match speed.

Clutches in an automatic and manual transmission function in a fundamentally different way.

 

[LTC8K6]

Does driving wear your tires?

 

[TanisHalfElven]

Does driving wear your tires?

Only in an automatic.
In a manual the car can forever run on the same tires.

 

[jlee]

Only in an automatic.
In a manual the car can forever run on the same tires.

Only if they're inflated to sidewall, though.

 

[Pacfanweb]

If you're burning out the clutch, it means you either suck at driving or you're driving like a lunatic.

I think the same thing might be said of you, if your automatic transmission fails in 5 years as you predicted earlier.

 

[JCH13]

I think the same thing might be said of you, if your automatic transmission fails in 5 years as you predicted earlier.

You missed it... his transmission has already been replaced.

 

[skyking]

I KNOW I'm wearing out my auto transmission in my truck. I'd be pleased to get 80,000 miles out of it. Something to do with 250 extra ft pounds of torque @ 1400 rpm.........

Only if they're inflated to sidewall, though.

Is there a Godwin's law regarding fleabag?

 

[LTC8K6]

Only in an automatic.
In a manual the car can forever run on the same tires.

What if I run the car while it's on jack stands? That would save my tires, but what about my transmission? Will it still gear hunt every 2.835 seconds?

 

[Bignate603]

What if I run the car while it's on jack stands? That would save my tires, but what about my transmission? Will it still gear hunt every 2.835 seconds?

Only if the trunk is full of rocks.