Recall Notice 21V-028 [1/28/21]: Manual Transmission / Clutch Overheat Covers All 2018-2021 Jeep Wranglers Produced by January 22, 2021

[Chazdog]

I am in the market for a used JL. After searching around I’ve found that dealerships are not selling any with the manual until the recall is fixed. This is annoying as hell. How can they just say we are working on it. Hell it was easier to make a covid vaccine than fix a transmission.

This is true, dealerships are stuck with CPOs that they can’t sell. Priority for Jeep was developing a fix for the 2021s so they could clear the STOP SALE order. One would think that the fix for the 2018-2020s would be close behind but not the case. This is what I just received from Jeep Chat: The remedy for Recall Y07 SAFETY 2018-2020 JL & 2020 JT SOFTWARE UPDATE 2018 - 20 - JL/JT is 6/24/2021.

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[DanW]

This is true, dealerships are stuck with CPOs that they can’t sell. Priority for Jeep was developing a fix for the 2021s so they could clear the STOP SALE order. One would think that the fix for the 2018-2020s would be close behind but not the case. This is what I just received from Jeep Chat: The remedy for Recall Y07 SAFETY 2018-2020 JL & 2020 JT SOFTWARE UPDATE 2018 - 20 - JL/JT is 6/24/2021.

I doubt the dealerships are feeling too much pain. There can't be that many manuals out there just sitting in inventory. They are typically custom ordered because they tend to sit on lots longer than they'd like, anyway.

As for June, no biggie to me. All it is is an insurance policy. Mine continues to put a smile on my face every time I drive it.

 

[Rock Crawler]

Are these clutch overheating problems happening at highway speeds on paved roads or at low speeds while crawling up long steep hills on rough dirt trails?

 

[Rubi6mt]

Ordered my JLUR 6-speed in mid Jan and received it end of February after trading in a 2020 Sport ALtitude 8-speed. (long story, but couldn't bond with the auto)

I've had numerous sticks from honda civics to T-5 mustangs to various T-56 GM vehicles and BMW's, all with pretty well defined clutch engagements. The JL clutch definitely took some getting used to. Its twin disc feels like a two step. Once i figured that I can launch from a dead stop on a steep hill smoothly releasing at 1,500rpm.

I think a big component is gearing. With the JLUR 4.10's, 4th is usable down to 35mph even on a slight grade. I can upshift into 5th at 50 and 6th at 55mph and maintain cruise.

When this clutch eventually goes, I will put in a CFII. The heavier flywheel should also help with the lack of off idle torque.

Otherwise extremely happy with this JLUR...going to Rausch Creek on Friday with a neighbor to run some trails including #11. Will see how it feels offroad.

 

[DanW]

Are these clutch overheating problems happening at highway speeds on paved roads or at low speeds while crawling up long steep hills on rough dirt trails?

They are mostly not happening at all, from what I've been able to gather. It was literally about two dozen cases out of over 44,000 and only 2 that experienced a catastrophic uncontained failure and one of those two resulted in a fire that destroyed the Jeep, according to what I've been able to gather. Those numbers may be off a little, but that's all I've found that I'd say could be confirmed. Only FCA and NHTSA know the exact number. It wouldn't be too far off, I'd be willing to bet.

The one that burned to the ground was apparently going up a slight hill at about 45mph, if I recall correctly. But by the time it failed, the damage was already done to the pressure plate from previous overheating, causing the metal to weaken and fracture. That one was described on this very forum awhile back, I'm pretty sure, by the unfortunate owner.

This is purely at most an educated guess: My best hunch is that the first recall addressed most of the ones that had an improper bleed and they did replace some clutches that were worn because of that. Again, only FCA knows, but some of those 2 dozen or so must have shown evidence of damage to the pressure plate, so they probably got either the appropriate new parts or possibly even entirely new transmissions. They also put protective sleeves and possibly other small parts to provide some measure of protection from flying debris in the event of another catastrophic uncontained failure. Those parts were pretty simple and straightforward and easy to create and put into place.

The 2nd recall, and I'm again giving my best guess, was a more complicated solution that required more time and testing to develop, and is more of an insurance policy, so it showed up later as a phase 2. It also requires no new parts, but only a change in code for the PCM. And that is the reprogram that is designed to detect clutch slip by precisely measuring the difference between wheel speed and engine speed in a given gear. Based on the difference, the heat build up would be pretty linear and known, thanks to the testing program, so the computer can basically predict or determine that X amount of slip for Y amount of time leads to a temperature of Z. If the value of Z gets above a certain threshold, the engine knows to retard power into a limp home mode until enough time and less or no slip is enough to bring Z down to a safe level, then power is restored. Of course if it happened even once, the wise thing to do would be to get it to a dealership ASAP to be diagnosed and fixed. Also, the threshold for Z to trigger the limp mode would include a pretty sizeable safety margin below the actual temp that causes the metal in the pressure plate to change and fracture, which is likely somewhere north of 1,000 degrees.

And before the defective pressure plate/clutch folks chime in, please understand that NO production pressure plate is designed to handle those kinds of temperatures. I don't even think racing applications can handle that. neither can clutches. So the problem lies in the slipping and what is causing it. Not in a defective clutch or pressure plate. If that were the case, mine would have self destructed a long time ago with the hard driving, off roading (2 trips to Moab among many others) and also towing I've put it through. It is closing in on 46k miles of flawless and smooth performance and has even taught 2 teens to drive a manual. (That's abuse in and of itself.)

This is all my best guess, and I don't work in the industry, nor am I an engineer or any kind of an expert. But it is based on open source information that has been put out by FCA or NHTSA and other bits and pieces and clues from too wide a range of sources to list. It could be wrong. But I've not seen anyone offer any evidence up to counter it, even partially, and I have had a source within FCA indicate that I was pretty warm. (No pun intended.)

So anyone who wants to can flame away! (No pun intended here, either) Lol!

 

[cripton805]

Has anyone re-geared to 4.88 with the manual? It will probably fry this clutch, but Im tired of my stock Sports gearing on top of the shitty feeling clutch and gearing. I can't stand the shit gearing anymore. Between a re-gear and a new clutch. I think I might just trade it in for am Automatic Mojave.

That's like 5k down the drain if Im not happy with it.

 

[DanW]

Has anyone re-geared to 4.88 with the manual? It will probably fry this clutch, but Im tired of my stock Sports gearing on top of the shitty feeling clutch and gearing. I can't stand the shit gearing anymore. Between a re-gear and a new clutch. I think I might just trade it in for am Automatic Mojave.

That's like 5k down the drain if Im not happy with it.

Why not fry it? It would actually make the gearing lower and more usable. Especially for a Sport, which is 3.23 or something like that. Even 4.10 would be night and day better. What size tire are you running?

 

[Spaffy]

Has anyone re-geared to 4.88 with the manual? It will probably fry this clutch, but Im tired of my stock Sports gearing on top of the shitty feeling clutch and gearing. I can't stand the shit gearing anymore. Between a re-gear and a new clutch. I think I might just trade it in for am Automatic Mojave.

That's like 5k down the drain if Im not happy with it.

I don't know what's different with my 2021, but I have no idea what the complaints are with the clutch anymore.

I love this clutch! Sport gearing could be better though. I have 4.88 gears stilling in my garage, waiting to be installed.

I posted the following in another thread:

I just wanted to post my initial thoughts on the manual in the Wrangler after the first 48 hours. I picked up my 2 Door Willys Sport, drove it the 60 miles home, and around town the past couple days. So this is INITIAL thoughts.

I absolutely LOVE it!

There are a lot of people complaining about how light the clutch is, how it engages, the fix etc.... The clutch *is* light; but Ive had other cars with a light clutch as well.... I have no issue with how light it is. I have no issue with how it engages. I think its brilliant!

I think what I notice more than anything with the transmission is just how quiet this 3.6 is! My last Jeep was a 1997 TJ. Compared to the TJ, this thing is a spaceship!

I love this manual, its smooth, clutch is fine, zero complaints about the manual. I have the B/W 3.5 inch screen and I can verify the gear display, its unobtrusive and in the top center of the screen. It looks like it always should have been there. It displays whatever gear I'm in.

The one thing I am going to mention: 3.45 gears. I don't fault Jeep in the slightest for putting these in here. It was a necessary evil to meet mileage standards. On my drive home on the freeway, I didn't even start to THINK about shifting into 5th gear until I was at 75-80 and I don't tend to drive that fast- I'm a cruiser. So essentially for me it's a 4 speed.

Jeep knows owners are going to modify Jeeps and axle gears are [in the grand scheme of things] easy! I'm thankful Jeep gave us enough transmission to handle lower axle gearing!

I have a set of 4.88s and OX-Lockers sitting on my floor. Those will be going in as soon as I have time. With how much gear I had left in the transmission I'm probably going to rock the 4.88s with the stock 32s and see how it goes. Ill report back with that when I do it!

 

[cripton805]

Why would that fry it? It would actually make the gearing lower and more usable. Especially for a Sport, which is 3.23 or something like that. Even 4.10 would be night and day better. What size tire are you running?

I offroad quite a bit. With hills and naturally ride the clutch. More aggressive gearing will probably burnt it up as it spools up. I went back to my stocks. I have the stock all terrains that came with the D30/D44 Anti Spin Diff package. LSD Diff.

I don't do much rock climbs. The occasional rocks that are in the way.

I was running 20x12s on 35" mud terrains.

It drove like shit stock, but even worse on mud terrains. I planned on regearing after my warranty ended, but I may just get an auto Mojave and regear that. Im not really happy with the clutch and gearing.

Although, I haven't found anything I couldn't climb on this Sport. I think the Mojave is better suited for me vs. Rubicon since I don't climb rocks. Occasionally intermediate articulation.

 

[cripton805]

I don't know what's different with my 2021, but I have no idea what the complaints are with the clutch anymore.

I love this clutch! Sport gearing could be better though. I have 4.88 gears stilling in my garage, waiting to be installed.

I posted the following in another thread:

You don't think the 4.88s are overkill for 32s? That thing is going to flip on its roof. haha

maybe, maybe not.

I drove an auto Rubicon with stock wheels / tires and it felt perfect on the highway.

 

[Spaffy]

You don't think the 4.88s are overkill for 32s? That thing is going to flip on its roof. haha

maybe, maybe not.

I drove an auto Rubicon with stock wheels / tires and it felt perfect on the highway.

The 4.88s are 100% overkill for the 32s, but probably not as much as you'd think.

Also depends on your driving style. I'm not really ever faster than 65-70 even on the freeway. No desire to be able to cruise at 85 all day.... It's a Jeep.

I posted this in another thread as well:

I'm going to be running the stock tires (Willys 32" mud terrain). At least at first. In time I may go somewhere between 33 and 35. Not in a rush.

Been playing with a gear calculator online using the stock tire sizes. The 4.88s will kick me up to almost 2400 RPM cruising at 65 in 6th (.72). That's a 700 RPM increase from the stock 3.45s with the 32" tires. That translates to about 400 RPM higher than an equivalent Rubicon on 33" tires.

I think that'll be acceptable and will make 5th and 6th gear very usable! I will be on the bleeding edge of having way too much gear for 32s though!

I used to run a TJ with the 4.0 and 5 Speed back in the day. 4.56 gears and 35 inch tires. That put me at 2250 RPM at 65 in 5th (.79) and it was great. If I put 35s on the JL it'll make it nearly identically geared to the TJ while highway crusing because of the 6th gear.

This 3.6 likes to rev a little higher than that old 4.0 as well though!

EDIT: FYI, even with the Sport 2.72 T-case 4.88 gears would bump you from a 48:1 to a 68:1 low gear crawl ratio. You shouldn't really be riding the clutch uphill. A lower crawl ratio would be beneficial in giving you that extra control and low and oomph.

Depending on how fast you drive you would be giving up speed from the top end.

 

[Jeepjunkie]

Has anyone re-geared to 4.88 with the manual? It will probably fry this clutch, but Im tired of my stock Sports gearing on top of the shitty feeling clutch and gearing. I can't stand the shit gearing anymore. Between a re-gear and a new clutch. I think I might just trade it in for am Automatic Mojave.

That's like 5k down the drain if Im not happy with it.

i have 4.56s and had 33” tires for a year, not super far off from 4.88 and 32“. I thought the 3.56 gears were awesome with 33”s. you’ll have slightly higher revs on the hiway than my set up, but no problems otherwise. I also wheeled my Jeep hard with the 33“ & 4.56 set up.
46,000 miles later, my son learning to drive stick on it and all that off roading, and the original clutch is still going strong.

 

[Toycrusher]

They are mostly not happening at all, from what I've been able to gather. It was literally about two dozen cases out of over 44,000 and only 2 that experienced a catastrophic uncontained failure and one of those two resulted in a fire that destroyed the Jeep, according to what I've been able to gather. Those numbers may be off a little, but that's all I've found that I'd say could be confirmed. Only FCA and NHTSA know the exact number. It wouldn't be too far off, I'd be willing to bet.

The one that burned to the ground was apparently going up a slight hill at about 45mph, if I recall correctly. But by the time it failed, the damage was already done to the pressure plate from previous overheating, causing the metal to weaken and fracture. That one was described on this very forum awhile back, I'm pretty sure, by the unfortunate owner.

This is purely at most an educated guess: My best hunch is that the first recall addressed most of the ones that had an improper bleed and they did replace some clutches that were worn because of that. Again, only FCA knows, but some of those 2 dozen or so must have shown evidence of damage to the pressure plate, so they probably got either the appropriate new parts or possibly even entirely new transmissions. They also put protective sleeves and possibly other small parts to provide some measure of protection from flying debris in the event of another catastrophic uncontained failure. Those parts were pretty simple and straightforward and easy to create and put into place.

The 2nd recall, and I'm again giving my best guess, was a more complicated solution that required more time and testing to develop, and is more of an insurance policy, so it showed up later as a phase 2. It also requires no new parts, but only a change in code for the PCM. And that is the reprogram that is designed to detect clutch slip by precisely measuring the difference between wheel speed and engine speed in a given gear. Based on the difference, the heat build up would be pretty linear and known, thanks to the testing program, so the computer can basically predict or determine that X amount of slip for Y amount of time leads to a temperature of Z. If the value of Z gets above a certain threshold, the engine knows to retard power into a limp home mode until enough time and less or no slip is enough to bring Z down to a safe level, then power is restored. Of course if it happened even once, the wise thing to do would be to get it to a dealership ASAP to be diagnosed and fixed. Also, the threshold for Z to trigger the limp mode would include a pretty sizeable safety margin below the actual temp that causes the metal in the pressure plate to change and fracture, which is likely somewhere north of 1,000 degrees.

And before the defective pressure plate/clutch folks chime in, please understand that NO production pressure plate is designed to handle those kinds of temperatures. I don't even think racing applications can handle that. neither can clutches. So the problem lies in the slipping and what is causing it. Not in a defective clutch or pressure plate. If that were the case, mine would have self destructed a long time ago with the hard driving, off roading (2 trips to Moab among many others) and also towing I've put it through. It is closing in on 46k miles of flawless and smooth performance and has even taught 2 teens to drive a manual. (That's abuse in and of itself.)

This is all my best guess, and I don't work in the industry, nor am I an engineer or any kind of an expert. But it is based on open source information that has been put out by FCA or NHTSA and other bits and pieces and clues from too wide a range of sources to list. It could be wrong. But I've not seen anyone offer any evidence up to counter it, even partially, and I have had a source within FCA indicate that I was pretty warm. (No pun intended.)

So anyone who wants to can flame away! (No pun intended here, either) Lol!

I'll chime in again on this thread.

1st off, these issues have only seemed to affect some of us, I was (am) an affected JL. For most, the dual clutch works as designed and is quite enjoyable. Jeep should have given everyone 4.10 gears as the 3.45 ratio is inappropriate for any 4wd vehicle, much less a Jeep.

For those with issues...
I've had my transmission up and down multiple times myself and spent some time messing with it. The clutch hydraulics leave much to be desired. For some earlier questions, the slave cylinder is about $60 and the master cylinder $100. Easy to replace, difficult to bleed properly.

Now for the big issue. The powertrain was not designed with a pilot bearing, and in fact, the input shaft does not even have suitable length to engage a pilot bearing if you wanted to add one. Through my studies of the system, it seems some transmissions have or have developed slop in the input shaft bearing inside the transmission allowing the input shaft to wobble. That wobble means the clutch disc(s) are rarely perfectly centered and also remain in contact with flywheel components even when disengaged, building heat when they shouldn't be. I feel this has been the root cause of those who failed spectacularly.

For those who have not failed spectacularly, it manifests itself as the wonky dual-engagement points in pedal travel, making smooth starts for experienced drivers difficult and random. That drove me nuts personally. The touchy throttle control just made the off-center clutch engagement issue even more unpredictable.

I upgraded to a dual friction Centerforce clutch and it made a world of a difference in driveability. The heavier flywheel makes nuetral revs slower and controllable. It also transforms the motor, giving it a very torquey feel and allowing you to crawl up obstacles even in Hi without having to feed any throttle.

However, the clutch does not fix the design deficiency of not having a pilot bearing and therefore no way keep the clutch centered if the internal main bearing has or develops play. That has resulted in the clutch still rubbing on the flywheel even when disengaged, making entering into 1st or reverse difficult at times.

I feel the software update is an underhanded bandaid to cover over the real issue of an insufficiently designed transmission system that would be incredibly expensive for them to remediate

 

[Kreepin1]

I'll chime in again on this thread.

1st off, these issues have only seemed to affect some of us, I was (am) an affected JL. For most, the dual clutch works as designed and is quite enjoyable. Jeep should have given everyone 4.10 gears as the 3.45 ratio is inappropriate for any 4wd vehicle, much less a Jeep.

For those with issues...
I've had my transmission up and down multiple times myself and spent some time messing with it. The clutch hydraulics leave much to be desired. For some earlier questions, the slave cylinder is about $60 and the master cylinder $100. Easy to replace, difficult to bleed properly.

Now for the big issue. The powertrain was not designed with a pilot bearing, and in fact, the input shaft does not even have suitable length to engage a pilot bearing if you wanted to add one. Through my studies of the system, it seems some transmissions have or have developed slop in the input shaft bearing inside the transmission allowing the input shaft to wobble. That wobble means the clutch disc(s) are rarely perfectly centered and also remain in contact with flywheel components even when disengaged, building heat when they shouldn't be. I feel this has been the root cause of those who failed spectacularly.

For those who have not failed spectacularly, it manifests itself as the wonky dual-engagement points in pedal travel, making smooth starts for experienced drivers difficult and random. That drove me nuts personally. The touchy throttle control just made the off-center clutch engagement issue even more unpredictable.

I upgraded to a dual friction Centerforce clutch and it made a world of a difference in driveability. The heavier flywheel makes nuetral revs slower and controllable. It also transforms the motor, giving it a very torquey feel and allowing you to crawl up obstacles even in Hi without having to feed any throttle.

However, the clutch does not fix the design deficiency of not having a pilot bearing and therefore no way keep the clutch centered if the internal main bearing has or develops play. That has resulted in the clutch still rubbing on the flywheel even when disengaged, making entering into 1st or reverse difficult at times.

I feel the software update is an underhanded bandaid to cover over the real issue of an insufficiently designed transmission system that would be incredibly expensive for them to remediate

Thanks for shedding some real world informed light on the matter. I can't believe they didn't design it with a pilot bearing. If I worked for FCA I'd be firing a couple of engineers right about now...

 

[cripton805]

For those who have not failed spectacularly, it manifests itself as the wonky dual-engagement points in pedal travel, making smooth starts for experienced drivers difficult and random. That drove me nuts personally. The touchy throttle control just made the off-center clutch engagement issue even more unpredictable.

I upgraded to a dual friction Centerforce clutch and it made a world of a difference in driveability. The heavier flywheel makes nuetral revs slower and controllable. It also transforms the motor, giving it a very torquey feel and allowing you to crawl up obstacles even in Hi without having to feed any throttle.

However, the clutch does not fix the design deficiency of not having a pilot bearing and therefore no way keep the clutch centered if the internal main bearing has or develops play. That has resulted in the clutch still rubbing on the flywheel even when disengaged, making entering into 1st or reverse difficult at times.

That's what mine feels like. It drives me crazy. I just avoid driving it altogether. My ex would avoid driving the Jeep too. Along with the constant correction / drifting in the steering. I've only driven my Jeep 14k miles in 24 months. I'm blessed to have a few different cars to choose from. Most of those miles. I drive about 600-700+ miles a week. I've really only driven my Jeep when it rains or I drive offroad / fun. Out of all of the cars I owned / have owned. I've driven it the least. If I didn't have other cars. I would have pulled out my hair or traded it in.

I noticed yesterday, the clutch / transmission was being extra sloppy. I noticed when I pressed the clutch entirely. I can feel a grind / gritty feeling on the pedal. I grinded the transmission gears at least 3-4x as if I was missing shifts. When I shift, I can feel the engagement of every gear super notchy. So either I'm just a terrible driver after 13 years of consistently driving stick, theres something wrong with mine, or it was designed poorly.

My mom gets scared when I take her on long trips in my Jeep. I tried to explain to her that the steering was designed to wander the road and the clutch / trans sounds are also normal. All while I'm fighting down shifting two to three gears up the smallest hills. lol

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