ShadowsPapa

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So these work backwards from prior hydraulic clutches?
In the older hydraulic clutches, they worked like brakes - you pushed the pedal which built pressure to the slave cylinder and the clutch was released.
Like brakes, if there was air in the system (they were not bled) you could never get the clutch to release because you could never build enough pressure to overcome the pressure plate force.
Lack of bleeding means air in the lines, air is compressible.
If you had air in the lines or in the slave or master cylinder, you compressed the air before building any pressure and ran out of pedal and the gears would grind because there wasn't enough travel to release the clutch.
Bleed the clutch system you get air out and then you can release the clutch fully.
In the systems I refer to - the clutch always had full force and could not be fully released.
If lack of bleeding - meaning there's AIR in the system, is the problem here - the hydraulic pressure holds the clutch engaged?????
Makes no sense to me.
Think of brakes - air in system (which is what bleeding REMOVES) means you can never fully apply the brakes as the air compresses, you can't build enough hydraulic pressure.
How does lack of bleeding keep the clutch from engaging IF this is a standard clutch pressure plate with springs holding it engaged?
Or is this some sort of clutch where hydraulic pressure KEEPS it engaged and there are no springs?
I've worked a fair share of hydraulic systems, including clutches, and replaced dozens of clutches over the years but this one must be some rocket science thing if lack of bleeding means it never fully applies.
Normally lack of bleeding means you can't release it fully and it drags.

Would love to see the schematic of the hydraulic system and a pic of the actual pressure plate.





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dakota.morgan91

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No, there's no software change that does that. If that were the case, you'd have to reduce it so much that nobody would want to keep their Jeep. So the pressure plate is not actually the problem, but rather is affected by the problem. If it was, they would simply replace the pressure plate.

So I will try to explain what the problem actually is, according to what I've been told and gleaned from a variety of sources, which I consider reliable and knowledgeable. My understanding (This is NOT from FCA directly, but rather from the sources.) It was explained to me that the defect is in the slave cylinder not being properly bled during manufacturing. The other parts are to protect vulnerable lines in case the pressure plate blows apart.

So that moves us to the pressure plate. If a Jeep has the problem where the slave cylinder was not properly bled, the clutch never fully engages, even with your foot completely off of it. This causes slipping, which even if slight, causes constant friction. It can heat up to almost around 1000 degrees, in extreme cases. On one of the Jeeps that burned to the ground, it was reported that the investigation estimated the pressure plate may have heated up closer to 1400 degrees. There is not a production street vehicle pressure plate in the world that can handle this kind of heat. So it weakens it or causes structural damage (I am not a metal expert, so I can't tell you exactly what happens, but only that it changes it and it is bad) and can then potentially fly to pieces and can bust out of the bell housing and sever those lines, causing a fire.

So the recall does not replace the pressure plate unless the clutch is prematurely worn and reprogramming the engine tune is NOT a part of the recall. Rather, they bleed the slave cylinder properly, then add the protective parts, such as a sleeve over one of the clutch fluid lines. They then check your clutch for wear, and if it fails the wear test, they replace it, too.

So here's the fun part. The wear check procedure goes something like this. Engage the parking brake. Put the transmission into 4th gear (maybe 3rd, but I can't remember). Run the engine to 4000rpm. Dump the clutch. If the engine stalls immediately, the clutch is not worn and passes the test. If the engine continues to run or struggle or sputter for any length of time, the clutch is worn and does not pass and must be replaced.

My dealer is pretty good, especially with clutches and manual transmissions. Still, I wanted to know for myself that my clutch was not worn. So I did the test. It passed, just like they said. They also reported that mine, like all the ones upon which they performed the recall, was properly bled from the factory and did not exhibit any issue, and again, it passed the wear test. So I'd imagine the ones with the problem were pretty few in number, although i do remember one or two folks on the JL forum saying they got a new clutch because theirs failed the test.

My Jeep got the protective parts and they bled it anyway. Recall complete. Nothing changed. It feels the same, accelerates the same, and is doing just fine after 41k miles, including a great deal of off roading and towing a boat. Power feels exactly the same. Actually, I'd say it feels even better as the engine has broken in, especially since about 20k miles. It feels stronger and like it revs more freely. But that had nothing to do with the recall. It felt that way before and after the recall.

So don't get too riled up about it. Chances are that your Jeep is fine. If you bought it since the recall, it has already been done, as it would have been illegal for them to sell it to you before completing it. Part of the delay in parts was to get the unsold vehicles fixed quickly.

If you had your vehicle back in May of 2020 and you still haven't gotten it done, then that might be on you. Get it in right away and get the parts ordered. If you bought it since then, check with FCA to confirm it was completed. Then don't worry about it.

Finally, like I said, mine is at 41k and has performed flawlessly from day 1. I'll come back and let you know if that changes. I wouldn't hold my breath for that.

And one other note. The transmission is rated for more torque than the 3.6 produces. Not a huge amount more, but certainly more. So reducing the torque output by even a small percentage would make no real difference, anyway. I've seen nothing from any source to indicate that a reprogram was a part of the solution. I think that's just rumor.
Why would the legal Document from FCA say something totally different? Can you source your claims or is this purely hear say? No disrespect, but I just ordered a manual JT and am genuinely curious what reality is.
 

dakota.morgan91

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So how on earth would the truck know what the temp of the clutch is and when tourque needs to be reduced? I have never heard of a "clutch temp sensor". Sounds fishy to me.
 

red/green hawk

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I've seen nothing from any source to indicate that a reprogram was a part of the solution. I think that's just rumor.
From page 4 of link

Part 573 Safety Recall Report 21V-028 Page 4
The information contained in this report was submitted pursuant to 49 CFR §573


Description of Remedy :

Description of Remedy Program : FCA US will conduct a voluntary safety recall on all affected vehicles to add software to reduce engine torque capability when clutch assembly temperatures rise to a level that may damage the inner pressure plate.

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


If the solution was bleeding the slave cylinder then why not just state it?
 

ShadowsPapa

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Why would the legal Document from FCA say something totally different? Can you source your claims or is this purely hear say? No disrespect, but I just ordered a manual JT and am genuinely curious what reality is.
I found a totally DIFFERENT clutch bulletin that talks about bleeding - that's not related to this one mentioned in the first post at all.

What DanW typed is almost word-for-word from the OTHER clutch bulletin - he typed FCA info.
So we're talking two different things here. Both are clutch heating issues, but the test he indicated and the bubbles are from a different bulletin. It's from April 2020 and covers only 2020 Gladiator and 18-20 Wrangler.
So the info DanW posted DOES come from FCA - but it's not the same bulletin we were talking about originally.
DanW quoting from an older bulletin (recall 20V-124) not the one red/green is quoting.
 
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ShadowsPapa

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No, there's no software change that does that. If that were the case, you'd have to reduce it so much that nobody would want to keep their Jeep. So the pressure plate is not actually the problem, but rather is affected by the problem. If it was, they would simply replace the pressure plate.

So I will try to explain what the problem actually is, according to what I've been told and gleaned from a variety of sources, which I consider reliable and knowledgeable. My understanding (This is NOT from FCA directly, but rather from the sources.) It was explained to me that the defect is in the slave cylinder not being properly bled during manufacturing. The other parts are to protect vulnerable lines in case the pressure plate blows apart.

So that moves us to the pressure plate. If a Jeep has the problem where the slave cylinder was not properly bled, the clutch never fully engages, even with your foot completely off of it. This causes slipping, which even if slight, causes constant friction. It can heat up to almost around 1000 degrees, in extreme cases. On one of the Jeeps that burned to the ground, it was reported that the investigation estimated the pressure plate may have heated up closer to 1400 degrees. There is not a production street vehicle pressure plate in the world that can handle this kind of heat. So it weakens it or causes structural damage (I am not a metal expert, so I can't tell you exactly what happens, but only that it changes it and it is bad) and can then potentially fly to pieces and can bust out of the bell housing and sever those lines, causing a fire.

So the recall does not replace the pressure plate unless the clutch is prematurely worn and reprogramming the engine tune is NOT a part of the recall. Rather, they bleed the slave cylinder properly, then add the protective parts, such as a sleeve over one of the clutch fluid lines. They then check your clutch for wear, and if it fails the wear test, they replace it, too.

So here's the fun part. The wear check procedure goes something like this. Engage the parking brake. Put the transmission into 4th gear (maybe 3rd, but I can't remember). Run the engine to 4000rpm. Dump the clutch. If the engine stalls immediately, the clutch is not worn and passes the test. If the engine continues to run or struggle or sputter for any length of time, the clutch is worn and does not pass and must be replaced.

My dealer is pretty good, especially with clutches and manual transmissions. Still, I wanted to know for myself that my clutch was not worn. So I did the test. It passed, just like they said. They also reported that mine, like all the ones upon which they performed the recall, was properly bled from the factory and did not exhibit any issue, and again, it passed the wear test. So I'd imagine the ones with the problem were pretty few in number, although i do remember one or two folks on the JL forum saying they got a new clutch because theirs failed the test.

My Jeep got the protective parts and they bled it anyway. Recall complete. Nothing changed. It feels the same, accelerates the same, and is doing just fine after 41k miles, including a great deal of off roading and towing a boat. Power feels exactly the same. Actually, I'd say it feels even better as the engine has broken in, especially since about 20k miles. It feels stronger and like it revs more freely. But that had nothing to do with the recall. It felt that way before and after the recall.

So don't get too riled up about it. Chances are that your Jeep is fine. If you bought it since the recall, it has already been done, as it would have been illegal for them to sell it to you before completing it. Part of the delay in parts was to get the unsold vehicles fixed quickly.

If you had your vehicle back in May of 2020 and you still haven't gotten it done, then that might be on you. Get it in right away and get the parts ordered. If you bought it since then, check with FCA to confirm it was completed. Then don't worry about it.

Finally, like I said, mine is at 41k and has performed flawlessly from day 1. I'll come back and let you know if that changes. I wouldn't hold my breath for that.

And one other note. The transmission is rated for more torque than the 3.6 produces. Not a huge amount more, but certainly more. So reducing the torque output by even a small percentage would make no real difference, anyway. I've seen nothing from any source to indicate that a reprogram was a part of the solution. I think that's just rumor.
Sorry, you are quoting a much older bulletin. It's not the same one.

The OP posted a NEWER one from this year,
you posted quotes from an April 2020 recall paper, 9 months old. I found the paper you quoted from you posted info from FCA almost word for word from April.

So apples and oranges.
One relates to the master cylinder, etc. - the other is indeed a programming thing.
Again - you are talking a very different bulletin than the OP of this thread is referring to.
 

dakota.morgan91

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I found a totally DIFFERENT clutch bulletin that talks about bleeding - that's not related to this one mentioned in the first post at all.

What DanW typed is almost word-for-word from the OTHER clutch bulletin - he typed FCA info.
So we're talking two different things here. Both are clutch heating issues, but the test he indicated and the bubbles are from a different bulletin. It's from April 2020 and covers only 2020 Gladiator and 18-20 Wrangler.
So the info DanW posted DOES come from FCA - but it's not the same bulletin we were talking about originally.
DanW quoting from an older bulletin (recall 20V-124) not the one red/green is quoting.
Got it!! thank you for the clarification! :)
 

mountainpass

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Feel free to delete if already posted, but I just got this alert on my GasBuddy app regarding a Overheated Clutch Recall.

For those with manual transmission, BOLO!

ED3F3ECF-4B14-4A2D-A67E-BCD1655DD347.png
Jeff can you edit the title to include something like "2nd All New Jan 21, 2028". The reason is I assumed it was you just now being aware of first recall.
 

ShadowsPapa

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It seems to me there could be as many as 3 different bulletins on this thing. And Jeff's appears to be new and the latest. The number before the V appears to be the year it was released so 21V means this year, 20V means last year, etc.
 

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So these work backwards from prior hydraulic clutches?
In the older hydraulic clutches, they worked like brakes - you pushed the pedal which built pressure to the slave cylinder and the clutch was released.
Like brakes, if there was air in the system (they were not bled) you could never get the clutch to release because you could never build enough pressure to overcome the pressure plate force.
Lack of bleeding means air in the lines, air is compressible.
If you had air in the lines or in the slave or master cylinder, you compressed the air before building any pressure and ran out of pedal and the gears would grind because there wasn't enough travel to release the clutch.
Bleed the clutch system you get air out and then you can release the clutch fully.
In the systems I refer to - the clutch always had full force and could not be fully released.
If lack of bleeding - meaning there's AIR in the system, is the problem here - the hydraulic pressure holds the clutch engaged?????
Makes no sense to me.
Think of brakes - air in system (which is what bleeding REMOVES) means you can never fully apply the brakes as the air compresses, you can't build enough hydraulic pressure.
How does lack of bleeding keep the clutch from engaging IF this is a standard clutch pressure plate with springs holding it engaged?
Or is this some sort of clutch where hydraulic pressure KEEPS it engaged and there are no springs?
I've worked a fair share of hydraulic systems, including clutches, and replaced dozens of clutches over the years but this one must be some rocket science thing if lack of bleeding means it never fully applies.
Normally lack of bleeding means you can't release it fully and it drags.

Would love to see the schematic of the hydraulic system and a pic of the actual pressure plate.
You may be right and I may have gotten it bass ackward. Either way the heat is being generated by the clutch rubbing on the plate when it should not be and that's caused by air in the system due to improper or incomplete bleeding. However, it would have to do it alot to build that kind of heat. So it may be when someone is sitting at a light with the clutch depressed.
 

mountainpass

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How exactly are they gonna know the clutch temperature? I guess add a sensor? Plus if I'm heating up the clutch on purpose I'm trying to do something I need the extra torque for. Man I was so close to getting a manual but the first recall made me wary. But I think yall that have them need to start a class action now.
Screenshot_20210203-171550_Drive.jpg


Edit: Link to new recall Check for Recalls: Vehicle, Car Seat, Tire, Equipment | NHTSA

Edit 2: the above screenshot is from the pdf imbedded in above link RCLRPT-21V028-2204.PDF (nhtsa.gov)
 

DanW

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How exactly are they gonna know the clutch temperature? I guess add a sensor? Plus if I'm heating up the clutch on purpose I'm trying to do something I need the extra torque for. Man I was so close to getting a manual but the first recall made me wary. But I think yall that have them need to start a class action now.
Screenshot_20210203-171550_Drive.jpg


Edit: Link to new recall Check for Recalls: Vehicle, Car Seat, Tire, Equipment | NHTSA
Ok, thanks for posting this.

Looks like there must be a temp sensor. Did not know that.

I don't think you can generate that kind of heat with one or two starts. You'd have to really cook that thing. One symptom is smelling a burning clutch during normal driving. Not just isolated situations.
 

ShadowsPapa

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You may be right and I may have gotten it bass ackward. Either way the heat is being generated by the clutch rubbing on the plate when it should not be and that's caused by air in the system due to improper or incomplete bleeding. However, it would have to do it alot to build that kind of heat. So it may be when someone is sitting at a light with the clutch depressed.
That would surely do it. You sit with your foot clear down at a light for 1 minute but the clutch isn't 100% released with any clearance at all, generating heat.
Hard to imagine getting THAT sort of heat from a single stop light but then in town........


My favorite hydraulic clutch experience was sitting in the city waiting for a light and the slave cylinder started to go - engaging the clutch at the least convenient time. Yikes, good thing I had a foot at the brake pedal to keep it from rolling a bit anyway.
So I drove the rest of the way through town unable to release the clutch - the cylinder died on me completely next light.

I keep spare master and slave cylinders on hand for my SX4 now - paranoid.
 

Rubi_Rhod

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The clutch temperature sensor thing seems weird. I don't think such readings exist.

**Total shots in the dark following**
I'm wondering if that 4k RPM drop test they did on the other recall would create the kind of conditions where this happens in normal driving.
Me personally, I am often in 4th at 3-5k RPM as there's a lot of hills around here. I'm wondering if some kind of sustained load like that would be something where the "design specifications" allowed for some level of slip at that kind of load, but as is the case from design on computer vs real world driving, that scenario would present itself more often leading to overheating.
That being said, that leads me to wonder if it's not a sort of temp measurement, but a calculation to reduce torque to limit slip based off load, time duration, RPM and other parameters already controlled for in the software.

edit: In other words, for the sake of argument and using round numbers to illustrate, if its allowed a degree of slip for every engine revolution, that's 360 rotations for the clutch to slip one whole revolution. Which may not be noticed in driving as "slip" but would definitely cause a lot of metal and mass to heat to such a high extent, and it would do so in a way that would be before the smoke point, as its all one big heat sink until it got to critical temps and... *boom*
**Total shots in the dark before**

All said, this is pretty concerning. I was a little worried after the first recall, as I hadn't yet bought my 6MT, but this seems like a weird defect, and an interesting resolution planned,. I would definitely like to know more facts, but not a lot of details is known or available from published sources.
 

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Am i the only one who is really aggrevated by this latest clutch recall. The fact that a year ago I got notice my 6 month old truck had a clutch recall was upsetting enough. Now to see a second recall is out and the solution isnt to fix the problem but to neuter my already under powered truck is upsetting. I paid $50,000 for a truck with 260 lb/ft of torgue not less. I have said since I test drove the truck the issue with it is it is underpowered. Not more then I could live with and I loved everything else so I could deal with the truck being a little underpowered. When on steep trails I already need to use 4 lo to get enough torque and rpm to prevent stalling without feathering the clutch. I didnt pay all this money for jeep to then lower my power instead of fixing the weak link. Its a cheap work around by a company that charges a premium for there product.
 

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