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

DanW

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What you describe in your last paragraph is NOT what happened to cause the fracturing. IT was not from simply wearing out. It was extreme friction over a short period of time that took the temperature to 1100 degrees. No normal wear condition will EVER take it to that kind of temperature.
Actually, the hydraulics are not in play in the video. Clutch pressure comes from the mechanical finger springs. Hydraulics are only used to open the clutch when changing gears.

And yes, a worn out clutch slipping while in gear can generate some pretty intense heat. Normal clutches generate enough smoke and smell to inform the operator that something is not right
When that video was taken, the damage had long ago been done. Read what he says about that.





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DanW

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Precisely my point. It would take some extreme slipping for am extended period to reach 1100 degrees. As experienced drivers, you recognized the issue before it became more serious. Even inexperienced drivers though would be unable to mistake the level of slippage (and smoke and smell) necessary to generate the full 1100 degree failure point
An experienced driver might not recognize it when the slipping is more subtle. Hard to say if you weren't driving the Jeep all that time. The hydraulic issue is more insideous. Driver error is more overt. Two different routes to the same result. Or even a third, which could be a combo of both. I'll bet the guy whose Jeep blew apart says he is a pretty good driver. And he might just be. His was what triggered the first recall.

The current fix covers both scenarios nicely.
 

Rharv

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I have a question I been really paying attention to my clutch lately and it feels like when I push on the paddle it’s hard and soft in some spots it also Creaking goes to the dealer on Monday for steering box and bubbles to be check out I wonder if they should take a look at the clutch as well recall was down back in March or April of 2020
 

sf5211

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I have a question I been really paying attention to my clutch lately and it feels like when I push on the paddle it’s hard and soft in some spots it also Creaking goes to the dealer on Monday for steering box and bubbles to be check out I wonder if they should take a look at the clutch as well recall was down back in March or April of 2020
I would mention it
 

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FlatSixShooter

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JeepCares said:
Hi everyone, there has been a lot of questions and different threads so I am going to post this and you may see the same info posted on other threads:

Towing capacity or performance will not be affected by this flash update.

There is no difference in the 3.6L engine's power output under "normal circumstances" with the Y01 flash. The torque reduction only happens if the engine controller calculates the clutch pressure plate temperature is above a certain temperature threshold.

The PCM monitors the engine RPM and the wheel speed sensors to determine if clutch slippage is occurring, how often, and at what intensity. Based on that information, the PCM calculates the clutch pressure plate temperature. The temperature threshold that reduces the engine torque is lower than the temperature needed to do permanent pressure plate damage. The vehicle cannot reach or exceed the temperature threshold under normal operating conditions, including towing and off-roading, and only occurs if the driver repeatedly slips the clutch, performs multiple, consecutive 2nd or 3rd gear launches, or if air is present in the hydraulic clutch system.

Kaitlin
Jeep Cares


So engine performance is reduced only when the re-engineered PCM CALCULATES it should be reduced, so the under-engineered clutch and pressure plate don't explode? So does every manual transmission vehicle made by all car companies require such power limiting software in case drivers do multiple 2nd/3rd gear starts and create excess slippage or do other clutch/pressure plates merely burn out but not explode?

In a better scenario, the (same?) engineers would have calculated how strong of pressure plate and clutch components should have been installed & needed, in all scenarios, for the engine(s) actually used. So do we believe the engineers will somehow get it right this time with software when they couldn't get it right with the pressure plates/clutch they designed & used?
 
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Kreepin1

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We all want to know the same thing - is this an actual defect or operator error? I've driven a 2012 with the old design, but am still waiting for delivery of a 2021 so what follows us pure speculation. I believe that there is no defect, rather a combination of design decisions that led to operator error. The proposed fix, if properly executed, will identify these errors and prevent sudden catastrophic failure - the three words every engineer dreads hearing.

Exhibit #1
Low pedal effort. FCA is working hard to make Jeeps more carlike and improve fuel economy. A twin disk clutch has many advantages. It is smaller, lighter and requires less pedal pressure than a single disk clutch. The fact that FCA adopted this design, given it's increased complexity and cost, shows just how hard they are trying. But this has backfired. The pedal is so light that people will sit at the light with the Jeep in gear and the clutch depressed. I suspect the often despised ESS contributes to this behavior as well, keep the clutch in and the engine keeps running...

Exhibit #2
Poor pedal feel. There are numerous threads complaining about the squeaky, gritty engagement mechanisms and poor feel for when the clutch begins to engage making it easy to stall the engine. Normally, the friction due to cheap plastic sleeves in the return spring and swelled o-rings in the slave cylinder wouldn't be noticed. But when combined with the low pedal effort in #1 FCA created a situation begging for operators to rev it up and slip the clutch to avoid stalling.

Exhibit #3
Disk drag. When the pedal is depressed, the friction disk in a single disk system is free to slide in and out on the splines of the transmission's input shaft. It basically seeks a spot where it is not touching the flywheel or pressure plate that are both spinning with the engine. A twin disk system is no different except there are now three things spinning with the engine and two disks connected to the transmission. The first picture is of a McLeod clutch similar to the one I installed in my CJ-7 last year. Note that both friction disks have been broached so they engage the transmission's input shaft. Now contrast that with FCA's design in the following two pictures (thanks to @Jebiruph for the pictures). The second picture shows the one and only disk that rides on the input shaft, I'll call this the inner disk as it's closer to the engine. In the third picture you see the rest of the assembly including the rusty sprocket of the outer disk (further from the engine) that piggybacks on a toothed gear thingy on the inner disk. Sorry about the confusing description :). From a torque transmission standpoint this contraption is fine. But I believe that it does not disengage as nicely. First, the gear driven outer disk has very narrow teeth. They are going to wear a small groove and want to stay in one spot rather than slide along the gear. Second, the splined inner disk must overcome a lot more friction due to the longer broached section. Third, which way and how far should this inner disk slide? It is getting mixed signals from two disks - one wants to slide towards the engine and one wants to slide towards the transmission. The end result is more friction than two independent disks.

McLeodClutch1024x1024.jpg


OEM_clutch2.jpg


OEM_clutch1.jpg


Conclusion
We don't know the driving habits of people that had this rare failure. I personally feel that the clutch design is fine, but the overall system encourages drivers to abuse the clutch. I know the vast majority of drivers are happy with the clutch and would buy a manual transmission again. I can't wait to get mine.
 

Kreepin1

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I find it funny this is for people who like to start out in 2nd or 3rd gear. If you're too lazy to start out in 1st gear.....dude get yourself an automatic.
LOL, you have so missed the point. By far the biggest challenge off road is that you simply can't shift on serious obstacles like steep sand dunes and muddy hills. You need momentum and wheel speed to clean the tires in these conditions and picking the gear you need to be in is both a joy and a curse.
 

LawrenceR

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Hello to all, I wanted to add my "two cents worth". It seems that most of the posts on this site is for complaints or negative responses - which is only to be expected. I thought a positive posting might help for some for those on the fence about purchasing a new Jeep or when those squeek's and odd noises come up.

I placed my order for a Willys, 2-door, V6, 6 spd manual in February 2020; I took delivery of it on July 01, 2020. I'm glad I held out for the manual.

My Jeep had to be one of the first off the line, since taking delivery of it, I have been nothing but pleased with it's performance.

One of the first things I noticed was how soft the clutch is. I'm 60 and grew up with manual transmissions. I've encountered "clutch smell" twice, both times were when backing up navigating some sandy soils and needing to slip the clutch a bit to maintain RPMs and traction.

I was very pleased with how LOW first gear is when in 4x4 LOW, my son and I were in Nevada, climbing some hills and was able to leave the foot off the gas and just let her climb over ruts and rocks without stalling.

I haven't needed to take my Jeep in for servicing yet, I have nearly 10,000 miles on her and have done the services myself - yes, being and "old school guy" I did my first crank case oil / filter change at 3000 miles - well before the system told me I needed to....

I'm not looking forward to the day when I need to see my dealer for service, I was not impressed with their service before taking delivery, hopefully the service department is better than the sales department.

All I can say is, I wish I bought a Jeep years ago...
 

sf5211

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LOL, you have so missed the point. By far the biggest challenge off road is that you simply can't shift on serious obstacles like steep sand dunes and muddy hills. You need momentum and wheel speed to clean the tires in these conditions and picking the gear you need to be in is both a joy and a curse.
Ok Kirk, Educate me please. I’ve never driven over a sand dune before. You take off in 2nd or 3rd from a stopped position? If so 2h, 4H, 4L?
I’m not trying to be a smart ass, I off-road in some back woods. I use 4 low 1st gear mostly but will occasionally shift to 2nd or use 4 high.
I could see how on sand you’d maybe want more speed. In the woods I drive like a granny and just take in the beauty.
 

Toycrusher

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Ok Kirk, Educate me please. I’ve never driven over a sand dune before. You take off in 2nd or 3rd from a stopped position? If so 2h, 4H, 4L?
I’m not trying to be a smart ass, I off-road in some back woods. I use 4 low 1st gear mostly but will occasionally shift to 2nd or use 4 high.
I could see how on sand you’d maybe want more speed. In the woods I drive like a granny and just take in the beauty.
Conditions vary, but I like to see a top wheel speed of 20mph roughly for soft sand. I run 4Lo and usually use gears 3-5. I don't have big dunes but if I'm climbing I usually stick to 3rd and try to avoid having to change. Stock 4.10 gears and 37s for reference. A non-Rubicon will need to run lower gears unless modified
 

Kreepin1

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Ok Kirk, Educate me please. I’ve never driven over a sand dune before. You take off in 2nd or 3rd from a stopped position? If so 2h, 4H, 4L?
I’m not trying to be a smart ass, I off-road in some back woods. I use 4 low 1st gear mostly but will occasionally shift to 2nd or use 4 high.
I could see how on sand you’d maybe want more speed. In the woods I drive like a granny and just take in the beauty.
Well Steve, the answer depends on the vehicle and the terrain. The motto "as slow as possible, as fast as necessary" is a good one to keep in mind.

Silver Lake Dunes is a good example. There are a series of dunes and it's over 100 feet up the first one called "Test Hill." I don't care how big your tires are or if you've got paddles or not, there is no way to crawl up this hill because of the soft fluffy sugar sand the last 5-10 feet at the top. In my Samurai you start in 3rd gear low range and need to be turning 5,000 rpm when you get to the end of the whoops and on the dune proper. Then there is a full throttle rush up the dune and you have to lift your foot off the gas and coast the last few feet to the top - unless you want to be like my daughter and "catch air" in which case you keep your foot in it.

TestHill.jpg


06_04SM.JPG
 

Toycrusher

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Well Steve, the answer depends on the vehicle and the terrain. The motto "as slow as possible, as fast as necessary" is a good one to keep in mind.

Silver Lake Dunes is a good example. There are a series of dunes and it's over 100 feet up the first one called "Test Hill." I don't care how big your tires are or if you've got paddles or not, there is no way to crawl up this hill because of the soft fluffy sugar sand the last 5-10 feet at the top. In my Samurai you start in 3rd gear low range and need to be turning 5,000 rpm when you get to the end of the whoops and on the dune proper. Then there is a full throttle rush up the dune and you have to lift your foot off the gas and coast the last few feet to the top - unless you want to be like my daughter and "catch air" in which case you keep your foot in it.

TestHill.jpg


06_04SM.JPG
Nice Sami. I have an 87 with a spring over and revolver shackles. Super flexy but worthless on the street. I started a 1.6 conversion a decade ago and haven't made much progress...
 

sf5211

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Well Steve, the answer depends on the vehicle and the terrain. The motto "as slow as possible, as fast as necessary" is a good one to keep in mind.

Silver Lake Dunes is a good example. There are a series of dunes and it's over 100 feet up the first one called "Test Hill." I don't care how big your tires are or if you've got paddles or not, there is no way to crawl up this hill because of the soft fluffy sugar sand the last 5-10 feet at the top. In my Samurai you start in 3rd gear low range and need to be turning 5,000 rpm when you get to the end of the whoops and on the dune proper. Then there is a full throttle rush up the dune and you have to lift your foot off the gas and coast the last few feet to the top - unless you want to be like my daughter and "catch air" in which case you keep your foot in it.

TestHill.jpg


06_04SM.JPG
Wow I guess spending my whole life in the city I’ve got a lot to learn. I’ve never even seen a sand dune that big or even knew they existed.
The beaches I went to growing up in NYC and visiting Long Island consisted of 6 inch sand dunes.
 

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