Clutch Recall (FCA W12 | 20V-124) on 2018-2020 JL Manuals [overheating clutch pressure plate]

[DanW]

There isn’t going to be a temp triggering a power cut. It’s going to be a permanent power cut reducing risk of slippage and thus reducing temps. Also, flashing CEL is only used for active misfire condition.

I think you are right, but If there were a sensor, I'd bet it could be programmed to throw a code and trigger a CEL light. Even if not a flashing one.

But the potential for harm is much greater with an overheating clutch in this case than any misfire. The worst the misfire would do is damage or destroy the engine. That ain't as big a deal as an exploding friction plate/bell housing and subsequent loss of power and a fire, which can hurt or kill someone. It could probably also be programmed to trigger a limp home mode or some other kind of visible and/or audible dash warning.

But it is all moot if there is no sensor, and it appears there is not.

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[DanW]

If they reduce the torque, our driving style may change to shift at higher revs which will negate the effect of the detune.
And there will be more slipping in the first gear as even the current torques is so low that you have to slip the clutch more than the usual to avoid stalling.

Actually, at least with 4.10 gears, there isn't much slipping at all in 1st gear. Certainly less than my JK or YJ or any other manual transmission I've had. This thing has the shortest first gear of any I've owned.

I am just skeptical that the detune really solves the problem. The more I think about it, the more I think that solution is really not going to be effective.

 

[ALRUI]

There are no sensors and if there were why would they have them to begin with? What would they control? Does anyone have the complete document that they can post here?

 

[JeepU4IA]

Um... that road is closed as well. CF is recalling their JL clutches due to a "Chewbaca" noise on some units (mine included). Supposed to be a fix sometime in late spring.

Okay. I've had mine for almost three years and 18,000 miles with no issues. I can wait a few more months. I'm certainly not going to let them detune my engine.

 

[Rodeoflyer]

I think this Schaffler group is the culprit. Aisin make the trans, they were the clutch supplier.

 

[DanW]

There are no sensors and if there were why would they have them to begin with? What would they control? Does anyone have the complete document that they can post here?

Ok, here is something posted on the Gladiator side that tells me there is some way to sense the temperature. Read the top paragraph. I can live with this if this can indeed be done this way, where the power is only reduced when the temps rise.

If they can sense the temp increase and trigger the detune, then a warning or limp home mode can be triggered. Clearly, if the temp ever rises like that, then something has gone wrong in a big way and it needs to be serviced IMMEDIATELY.

What I won't accept is a permanent and full detune of my engine. If the tranny/clutch is operating normally, at normal temperatures, then it should be allowed to produce full power.

If there is no sensor in the clutch/plate area, I'm wondering if the high temp would trigger a sensor in the engine or in the transmission itself. It is an aluminum housing, so if you get to those high temps I would imagine it would conduct the heat elsewhere where even a slight rise could be interpreted as an indicator of a problem, triggering the program to retard power.

Of course, that's just wild speculation. But we seem to have two different descriptions of how the software change would work.

We need a better understanding of exactly how this works. Jeep has some serious explaining to do here.

 

[beaups]

Ok, here is something posted on the Gladiator side that tells me there is some way to sense the temperature. Read the top paragraph. I can live with this if this can indeed be done this way, where the power is only reduced when the temps rise.

I like the wording of that a lot better, I just can't see how. But guess we will see.

 

[mgroeger]

Ok, here is something posted on the Gladiator side that tells me there is some way to sense the temperature. Read the top paragraph. I can live with this if this can indeed be done this way, where the power is only reduced when the temps rise.

Million dollar question... how are they detecting temp? There is no temp sensing equipment in that area that can detect the temp of the clutch.

 

[DanW]

Here is the document where it states that the detune occurs when the temps rise to a danger point:

https://static.nhtsa.gov/odi/rcl/2021/RCLRPT-21V028-2204.PDF

So there seems to be a discrepancy between this NHTSA document and what was posted earlier that appears to be from FCA. (Or was it?)

So my question remains. Is the detune full time, even if there is no problem in the clutch/transmission, or does it kick in when the temps rise to a danger point? I find the former to be an unacceptable solution. However, I can live with and would be fine with the latter.

@JeepCares, can you find out how the heck this new solution is supposed to work?

 

[Mr Lee]

I suspect they are running a algorithm that compares clutch pedal position, rpm, time between applications and speed.. They use this in other circumstances to calculate data.

 

[DanW]

It's hard to believe there are sensors in the clutch mechanism that measure temperature.

Maybe they are in the transmission. The thing has an aluminum housing which would quickly conduct heat. With a dramatic rise in heat in the clutch and pressure plate, it would register in the transmission relatively quickly, I would guess. When a temp sensor in the transmission (if there is one) detects a rise to a certain point above normal, the PCM could be programmed to trigger the detune.

I just don't know if there is any sensor at all in the tranny. I would imagine there is, but who knows? Or, maybe it would trigger one of the multitude of sensors in the engine that might be near the transmission or bell housing?

I just want to know that the detune only happens when there is excessive heat, not when all is within the normal temp range. Like I said, I could live with that. And I'd bet mine won't experience it. Otherwise, if there was any way I could, I'd roll the dice. I'm ocnfident mine has not had the problem that leads to the overheated friction plate. Not after 41k of driving it hard.

 

[DanW]

I suspect they are running a algorithm that compares clutch pedal position, rpm, time between applications and speed.. They use this in other circumstances to calculate data.

You may be right. There are enough electronics and sensors in these things to likely give them multiple ways to skin a cat.

 

[DanW]

I’m not sure if you guys have seen this, but I received an email today with this info. The remedy is now to reduce engine torque. Smh.

So this is an NHTSA document, too. Look at the wording under the remedy. Then look at this other NHTSA document and the wording for the remedy. Two different things there. This one indicates clearly that the detune would only occur when triggered by high temps.

So I need to chill out and calm back down and wait to hear what FCA says about it, rather than some government bureaucrat in a cubicle in DC who probably did not fully understand or read what FCA said they were going to do. So I'm taking a deep breath right now and telling myself they are not going to F-up my wonderful Jeep by stealing its Pentastar mojo.

https://static.nhtsa.gov/odi/rcl/2021/RCLRPT-21V028-2204.PDF

 

[intentsrig]

So this is an NHTSA document, too. Look at the wording under the remedy. Then look at this other NHTSA document and the wording for the remedy. Two different things there. This one indicates clearly that the detune would only occur when triggered by high temps.

So I need to chill out and calm back down and wait to hear what FCA says about it, rather than some government bureaucrat in a cubicle in DC who probably did not fully understand or read what FCA said they were going to do. So I'm taking a deep breath right now and telling myself they are not going to F-up my wonderful Jeep by stealing its Pentastar mojo.

https://static.nhtsa.gov/odi/rcl/2021/RCLRPT-21V028-2204.PDF

Either way this is a poorly designed clutch assembly. They are cutting power because the pressure plate is not able to keep the clutch from slipping..maybe weak springs?

With an 11 1/8” clutch disc/ pressure plate clamp surface should be more than enough to deal with our measly 260lb of torque.

My father in law has a gt350 mustang he races with around 400hp/tq and 11” clutch disc. Same clutch since 2012! That’s 9 years of racing on that clutch. Took it out recently to rebuild the motor and it didn’t even look half bad.

Jeep went cheap with our clutch/ pressure plate or perhaps the company making them.

 

[DanW]

Either way this is a poorly designed clutch assembly. They are cutting power because the pressure plate is not able to keep the clutch from slipping..maybe weak springs?

With an 11 1/8” clutch disc/ pressure plate clamp surface should be more than enough to deal with our measly 260lb of torque.

My father in law has a gt350 mustang he races with over around 400hp/tq and 11” clutch disc. Same clutch since 2012! That’s 9 years of racing on that clutch. Took it out recently to rebuild the motor and it didn’t even look half bad.

Jeep went Jeep with our clutch/ pressure plate.

I don't think that is necessarily the case. I think it works fine and can easily handle the torque when all is as it should be. If not, mine would have blown apart a long time ago. I run it HARD and it has 41k on it now. The ones that blew up had FAR fewer miles on them and I'd bet were not run nearly as hard.

I still think this goes back to some of them not being bled properly, even during the first recall. They are not all slipping and generating 1100 degrees of heat. Only a very few have actualy done it to the point of being identified. 13 as of a year ago. Clearly it has reappeared in some after the recall, or we wouldn't be seeing this. But I still think it is a small number. If a design flaw, all of them would exhibit the conditions unless hardly driven.

I've really driven the piss out of mine. Works fine. Feels great. Feels no different than when new. Passed the clutch wear test twice.

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