Traditional torque converter vs multi-plate clutch

[gregk24]

I'll be the first to admit, I am not a transmission expert. I understand the basics, but I am a little fuzzy on how the torque converter works. Anyway, my question is...compared to the traditional fluid filled torque converter, how do multi-plate clutch types compare LONGEVITY wise?

The new 2019 Jetta's are equipped with one of these multi-plate clutch torque converters, vs the previous generation which has a traditional one. This I presume is in an effort to increase MPG. I wonder though, will long term reliability be sacrificed? How long have these been around? I have never heard of them until reading about the new 8 speed auto recently. Also, to clarify the transmission itself is a regular automatic, not the DSG.

 

[Colt45ws]

Point a powered fan at a fan thats not running. Now put both fans in a box and fill it with fluid. Thats a torque converter.

I dont know the details of that but I assume they are just using a multi-plate lockup clutch inside the converter. So it will act like every other converter made for the past 30 years where a clutch can be computer activated to eliminate the loss through the converter. I would guess they are using it more aggressively and so they need the higher holding capacity of a multi plate. Most lockups are single plate, so they can't transfer a lot of torque without slipping. With a multi plate they will have more torque capacity with the lockup engaged. Ergo they can leave it in lock up at higher throttle input that would usually require a unlock. They might even be locking up shortly after take off and leaving it locked until you are getting stopped.

Pretty much every automatic made has a multi-plate clutch pack in it some where, so its not new, just they are putting it inside the converter.

 

[gregk24]

Originally Posted by Colt45ws
Point a powered fan at a fan thats not running. Now put both fans in a box and fill it with fluid. Thats a torque converter.

I dont know the details of that but I assume they are just using a multi-plate lockup clutch inside the converter. So it will act like every other converter made for the past 30 years where a clutch can be computer activated to eliminate the loss through the converter. I would guess they are using it more aggressively and so they need the higher holding capacity of a multi plate. Most lockups are single plate, so they can't transfer a lot of torque without slipping. With a multi plate they will have more torque capacity with the lockup engaged. Ergo they can leave it in lock up at higher throttle input that would usually require a unlock. They might even be locking up shortly after take off and leaving it locked until you are getting stopped.

Pretty much every automatic made has a multi-plate clutch pack in it some where, so its not new, just they are putting it inside the converter.


So in that case, it seems a traditional torque converter has less wear vs the multi-plate. However, I suppose if designed properly, the multi plate t/c could still last as long. It just seems that it would have more wear with every stop / go vs a regular t/c.

 

[maxdustington]

There was a recent rental review thread on a 2019 Jetta 1.4/auto and the OP complained that it would lug every gear. I'll bet you the need the clamping pressure for that. I think he mistook it for a initially DSG because of how jerky it was, too.

 

[gregk24]

Originally Posted by maxdustington
There was a recent rental review thread on a 2019 Jetta 1.4/auto and the OP complained that it would lug every gear. I'll bet you the need the clamping pressure for that. I think he mistook it for a initially DSG because of how jerky it was, too.


I am familiar with how they drive, I have driven a 2019 SE (auto). I agree it can be jerky on downshifts, and it is programmed to hold RPM's low. However, the 1.4 TSI makes peak torque at 1400 rpm so your still scooting along just fine.

 

[red7404]

like Gregk24 iam not a transmission expert. but a car i had with an automatic in the late 60s. a 1965 Chrysler 300 L . i would turn on to my dirt street. at 15 mph i would open the 4 bbls but it would stay in 3 rd gear. and move the dirt , both tires. made me think the torque converter was truly multiplying the torque. i think a stick trans wouldn't do that.

 

[CT8]

Two fans pointing at each other is a fluid coupling. Put a stator in between the two fans that then it becomes a torque converter. A fluid coupling doesn't increases the torque . A torque converter does,. The clutch/s eliminates the slippage of the fluid coupling.

 

[SteveSRT8]

haha, nice primer.


Mercedes was equipping some of their higher performing AMG variants a few years ago with multi plate clutches in place of torque converters, still coupled to their 7 speed auto. Never equated that design with longevity, but there were remarks about it generating less heat and being more efficient...

 

[Cujet]

Transmissions like the DSG are dual clutch units. With the exception of starting off the line in 1st gear, the clutches share the wear. With each clutch operating only 3 specific gears.

A well designed one should last a very long time.

 

[KrisZ]

The reason multiple clutch plates are used on the torque converter is to allow TC lock and unlock in every gear past 1st. TC lock is very important for fuel economy because a fluid coupling always slips and generates heat, instead of transferring all the power. Hence TC lockup is implemented.

In the past the TC would only lock up in the final gear, once certain speed was reached. Then manufacturers in 5 speed and higher gear transmissions started locking up TC in few top gears, like 4th and 5th, or 4th, 5th and 6th. But to get the most furl economy and efficiency, it's best to keep the TC locked in as many gears as possible and for as long as possible. That is why multiple clutch plates are implemented. They provide the surface area needed to constantly lock and unlock the TC. Also, a mult-plate design can be packaged smaller than a one big, single plate clutch.

 

[IndyIan]

If you do lots of highway driving I'd think the clutch would last as long as anything as its not shifting that much, and once you are moving it probably slips very little with each shift. If you live in a hilly city like S.F. then a computer controlled clutch may not be a great thing, even a wet-multiplate... On your test drive see how much the programming is trying to simulate an actual torque converter. If its slipping much at all after you get moving then maybe look else where.