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

[JohnT]

my theory - and it's just a theory and based on the fact that i have driven standards for some 45 years (and never lost a clutch - even racing) AND after 18 months with this particular jeep I still feel like it's my first time driving a standard:

The engine is quirky at low revs. Has a weird torque thing happening that feels something like the early days of turbochargers. This is fine in an automatic vehicle, as it gives that head-snapping feeling when you give it a bunch of gas off the stop line. Makes it "feel" like the car has a ton of power, and follows up rather disappointingly (but, hey- it's a jeep). Anyhow - in a standard, combined with a new, 'touchy' clutch it's a beast to roll away from a stop light elegantly. I am thinking, that Jeep has discovered that perhaps there have been failures from too much feathering by those who don't understand that you can overheat a clutch. If you do it wrong, you can find yourself feathering the clutch all the way through 3rd gear... not a good way to drive a standard.

And perhaps is that the reason said "software" is so delayed, is that "software" probably won't fix the problem (unless it is to sort out that engine torquey feeling).

Anyhow - just a theory. After 18 months with this vehicle, I am starting to get comfy with the clutch/engine matchup. Then I jump in my '04 TJ, or my son's '17 JK and drive it around a bit and i am back to square one for a few weeks.

The PR behind all this is a bit strange - I get the recall notice that says we don't have the parts, do a bit of research and find out that parts = software fix as well as 'exploding bits' and can imagine how people feel uneasy driving a deathtrap . All the same, I don't care - just wanna drive my jeep. (and maybe get the dealer to fix the stereo USB thing - WAY more annoying than a recall notice).

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[nomographer]

combined with a new, 'touchy' clutch it's a beast to roll away from a stop light elegantly.

What does this mean? Let out the clutch and it will roll without stalling; right?

Is your issue the clutch or the accelerator pedal? In neutral, what's the lowest RPM you can hold above idle?

 

[JohnT]

What does this mean? Let out the clutch and it will roll without stalling; right?

Is your issue the clutch or the accelerator pedal? In neutral, what's the lowest RPM you can hold above idle?

means without stalling or jack-rabbiting. The accelerator pedal is fine except if you tap it lightly the revs go way beyond 2000. Idle is just over 500 I guess (normal). You realllly have to feather the clutch (way more than I would consider normal) to roll without stalling. (and btw, the hill-start assist or whatever is called is turned off). I always just called it a timing issue (left foot/right foot timing), but this is chronic lol.

 

[Kreepin1]

means without stalling or jack-rabbiting. The accelerator pedal is fine except if you tap it lightly the revs go way beyond 2000. Idle is just over 500 I guess (normal). You realllly have to feather the clutch (way more than I would consider normal) to roll without stalling. (and btw, the hill-start assist or whatever is called is turned off). I always just called it a timing issue (left foot/right foot timing), but this is chronic lol.

Have you re-calibrated your accelerator? Mine is not like that at all. Very easy to roll away without stalling.

 

[OldGuyNewJeep]

Have you re-calibrated your accelerator? Mine is not like that at all. Very easy to roll away without stalling.

+1

 

[nomographer]

if you tap it lightly the revs go way beyond 2000

It's fly by wire. The accelerator pedal has an electronic sensor that feeds the ECM or somesuch. When the system is flashed the ECM doesn't seem to know the actual range of the sensor (possible voltage/resistance output values), so it's basically either On or Off (less throttle or more throttle), and I have reason to believe it never "learns". The Y01 wiped out mine; it was the first thing I checked when I started it. It's not part of their procedures, nor did my dealer do it as part of the arrival inspection.

Get in vehicle, put on seat belt, press button twice to put it into Run (no ignition / engine off). Wait for the engine light then slowly go the full range on the accelerator pedal, five seconds down, five seconds up, repeat. (Arguably one is enough). Thirty seconds seems to be too long, two seconds means it'll likely miss some of the blank spots in the sensor output (so you could get dead zones). Foot off accelerator, neutral, clutch in, hold for ignition.

Feather your accelerator pedal now and see what RPM it holds.

 

[JohnT]

It's fly by wire. The accelerator pedal has an electronic sensor that feeds the ECM or somesuch. When the system is flashed the ECM doesn't seem to know the actual range of the sensor (possible voltage/resistance output values), so it's basically either On or Off (less throttle or more throttle), and I have reason to believe it never "learns". The Y01 wiped out mine; it was the first thing I checked when I started it. It's not part of their procedures, nor did my dealer do it as part of the arrival inspection.

Get in vehicle, put on seat belt, press button twice to put it into Run (no ignition / engine off). Wait for the engine light then slowly go the full range on the accelerator pedal, five seconds down, five seconds up, repeat. (Arguably one is enough). Thirty seconds seems to be too long, two seconds means it'll likely miss some of the blank spots in the sensor output (so you could get dead zones). Foot off accelerator, neutral, clutch in, hold for ignition.

Feather your accelerator pedal now and see what RPM it holds.

wow - awesome. I will give that a try. thanks

 

[JohnT]

Have you re-calibrated your accelerator? Mine is not like that at all. Very easy to roll away without stalling.

OK... did the recalibration, and I owe you a beer (and I retract my theory stated a few posts earlier). The Rubicon starts off the line EXACTLY the way I expect it to. All is good. Thanks for the hint.

 

[nomographer]

You know I'll just be slightly abusive of my forum membership here...

@JeepCares the accelerator sensor calibration needs to go into the Y01 procedure, and maybe in dealer arrival inspections or main assembly line process somewhere.

The Y01 flash clears the sensor values, and it doesn't seem calibrated at the factory (it wasn't in my 2021 in January), so the accelerator pedal truly only supports an Off/idle state, and an On/full power state.

I don't know if the software in the automatics somehow learns the values, but in my first four days of ownership, with daily test drives, it stalled on any attempt to use the accelerator pedal from a stopped position, except with the accelerator way down and then it would always burn rubber. Recalibrating the sensor went from twelve stalls per hour to zero.


For what it's worth, thanks for listening. I know of no other mechanism to provide QA/QC feedback.

 

[Toycrusher]

A fractured inner plate would come flying out the second you depress the clutch pedal. And I already did the math, 3.4 minutes to reach 1,100 degrees from operating temperature. The next time you finish a long drive, crawl under the Jeep and put your hand on the bellhousing. You are gonna be shocked at how hot it is.

Let me know when you're tired of wrestling with the pig

Just gotta say, on my '18, both pressure plates are pretty well trapped. Obviously shrapnel "exited the building" as it were, but I haven't seen any documentation of what precisely came apart first. Was it the pressure plate friction surface? Motor or Transmission side? Was it the outer housing? I've extracted plenty of smoke and smell from my original clutch assembly, how did these reach the point of 1100 degrees without first filling the cab with smoke? Does the friction disc have THAT much grip that it wouldn't melt and start slipping BEFORE getting the pressure plate assembly reached 1100 degrees? Why does every other clutch assembly produced in the last hundred years have the friction material fail resulting in slippage rather than a complete assembly disintegration?

And finally, how does anyone successfully keep it from stalling for three+ minutes while dragging this bad without giving up and just putting it in neutral?

 

[nomographer]

And finally, how does anyone successfully keep it from stalling for three+ minutes while dragging this bad without giving up and just putting it in neutral?

Presumably all the extra speaker options are so loud that they can't hear all the warnings. Maybe when the clutch overheats the software should turn off the radio.

 

[JeepCares]

You know I'll just be slightly abusive of my forum membership here...

@JeepCares the accelerator sensor calibration needs to go into the Y01 procedure, and maybe in dealer arrival inspections or main assembly line process somewhere.

The Y01 flash clears the sensor values, and it doesn't seem calibrated at the factory (it wasn't in my 2021 in January), so the accelerator pedal truly only supports an Off/idle state, and an On/full power state.

I don't know if the software in the automatics somehow learns the values, but in my first four days of ownership, with daily test drives, it stalled on any attempt to use the accelerator pedal from a stopped position, except with the accelerator way down and then it would always burn rubber. Recalibrating the sensor went from twelve stalls per hour to zero.


For what it's worth, thanks for listening. I know of no other mechanism to provide QA/QC feedback.

Hi nomographer,
Thank you for taking the time to provide your honest feedback. We will make sure to document accordingly!

Rob
Jeep Cares

 

[MountiesNGamecocks]

It's fly by wire. The accelerator pedal has an electronic sensor that feeds the ECM or somesuch. When the system is flashed the ECM doesn't seem to know the actual range of the sensor (possible voltage/resistance output values), so it's basically either On or Off (less throttle or more throttle), and I have reason to believe it never "learns". The Y01 wiped out mine; it was the first thing I checked when I started it. It's not part of their procedures, nor did my dealer do it as part of the arrival inspection.

Get in vehicle, put on seat belt, press button twice to put it into Run (no ignition / engine off). Wait for the engine light then slowly go the full range on the accelerator pedal, five seconds down, five seconds up, repeat. (Arguably one is enough). Thirty seconds seems to be too long, two seconds means it'll likely miss some of the blank spots in the sensor output (so you could get dead zones). Foot off accelerator, neutral, clutch in, hold for ignition.

Feather your accelerator pedal now and see what RPM it holds.

This seems to have done good things to my jeep. Thanks!

 

[nomographer]

This seems to have done good things to my jeep. Thanks!

Next to fuses, I'd say this is the second item on the checklist for all new manual transmission owners. The very first time I tried it, after four days of new-owner practice driving, stalling it five times per hour, it didn't really work; I think I moved the pedal too slowly. Second attempt though, maybe 10sec down, 10sec up, it worked.

It's literally a versus difference.


ps I have not yet tried to trick it by starting with the pedal slightly down so there's more of a "dead zone", but that might make it less 'sensitive to tapping'. Who wants to try it?

 

[Rodeoflyer]

It's fly by wire. The accelerator pedal has an electronic sensor that feeds the ECM or somesuch. When the system is flashed the ECM doesn't seem to know the actual range of the sensor (possible voltage/resistance output values), so it's basically either On or Off (less throttle or more throttle), and I have reason to believe it never "learns". The Y01 wiped out mine; it was the first thing I checked when I started it. It's not part of their procedures, nor did my dealer do it as part of the arrival inspection.

Get in vehicle, put on seat belt, press button twice to put it into Run (no ignition / engine off). Wait for the engine light then slowly go the full range on the accelerator pedal, five seconds down, five seconds up, repeat. (Arguably one is enough). Thirty seconds seems to be too long, two seconds means it'll likely miss some of the blank spots in the sensor output (so you could get dead zones). Foot off accelerator, neutral, clutch in, hold for ignition.

Feather your accelerator pedal now and see what RPM it holds.

Not to mention the fact that it's ridiculous the customer would have to do this. I tried this and it had no effect...

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