Vibration when decelerating in manual transmission

[foggybuzzard]

2023 3.6 Pentastar with manual transmission.
Stock
All terrain tires
3,100 miles
When downshifting to decelerate, regardless of gear, there is intermittent vibration.
When I depress the clutch, the vibration immediately goes away and resumes when I let the clutch out.
I don’t notice it when accelerating in any gear, but I notice it when decelerating in 4th and especially 3rd and 2nd gears.
The vibration reminds me of having mud tires and going like 3 mph where you can feel the tread bumps as the tire rotates.
The vibration may be there at 6th & 5th gear, but maybe going too fast for me to notice. It doesn’t seem to be related to rpms, but does seem to be related to speed. For example, I notice it consistently in 2nd / 3rd gear at around 25 mph.
I thought it was tire/suspsension/alignment related, but like I mentioned, as soon as I put in the clutch and coast, the vibration goes away and it feels nice and smooth.
Just when decelerating.
I tried searching with a variety of phrases but not finding similar report in the forum.
Wondering if clutch would slip on deceleration but not acceleration?
I’ve engaged 4wd and the rear locker, then disengaged both, and not noticing any change.
Narrowing thoughts of scope to clutch, transmission, driveline, rear differential. Curious to get thoughts on where else to look, where to start.

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[PuddleJumper]

sounds like shuddering. I'd bet thats an OE clutch issue from improper install or a faulty part.

 

[Janster]

Are you still under warranty? Driveline should be warranties for 60K.

The first thing I thought of…. Driveshaft angle. Do you have a lift?

 

[Sandman 4x4]

2023 3.6 Pentastar with manual transmission.
Stock
All terrain tires
3,100 miles
When downshifting to decelerate, regardless of gear, there is intermittent vibration.
When I depress the clutch, the vibration immediately goes away and resumes when I let the clutch out.
I don’t notice it when accelerating in any gear, but I notice it when decelerating in 4th and especially 3rd and 2nd gears.
The vibration reminds me of having mud tires and going like 3 mph where you can feel the tread bumps as the tire rotates.
The vibration may be there at 6th & 5th gear, but maybe going too fast for me to notice. It doesn’t seem to be related to rpms, but does seem to be related to speed. For example, I notice it consistently in 2nd / 3rd gear at around 25 mph.
I thought it was tire/suspsension/alignment related, but like I mentioned, as soon as I put in the clutch and coast, the vibration goes away and it feels nice and smooth.
Just when decelerating.
I tried searching with a variety of phrases but not finding similar report in the forum.
Wondering if clutch would slip on deceleration but not acceleration?
I’ve engaged 4wd and the rear locker, then disengaged both, and not noticing any change.
Narrowing thoughts of scope to clutch, transmission, driveline, rear differential. Curious to get thoughts on where else to look, where to start.

If the issue goes away when you depress the clutch pedal, sound like a pilot bearing, or throw out bearing.

 

[foggybuzzard]

No lift - all stock.
I know I can go in to dealer, but they are a couple weeks out and thought I would check here to see if anybody else has had similar, so I could coach the dealer with some guidance on things to check.
But, I’ll let them do their thing.

The moderator moved my thread into this “Issues, repairs, warranty…” group and after that I found similar threads on this topic. Apologies for cluttering up the forum with duplicate threads, my original search wasn’t returning the similar threads.
What I’m noticing in my case (with the shuddering) is on deceleration whereas the other posts are on acceleration, but it’s probably same root cause. One of the threads there are some assertions that it’s the clutch pedal vibrating. I’ll use my foot to play with that and see if it’s similar, and wait for my dealer appointment to roll around.
Will also comment in the other similar thread and refresh that one, since it has more insight (8 pages of posts).
Appreciate the responses / perspectives.

 

[foggybuzzard]

If the issue goes away when you depress the clutch pedal, sound like a pilot bearing, or throw out bearing.

Good point - yeah, thinking it’s in that clutch assembly.

 

[bllprk402]

This is the design of the twin disc - dual mass flywheel system. I don't think most people downshift. The dual mass flywheel is only going to like to engage in a single direction (acceleration). I doubt anything is wrong, its how it was designed.

Totally wrong clutch for this jeep. :-(

 

[foggybuzzard]

I’m not opposed to going aftermarket…
If there is a right clutch for it.

Getting a free clutch under warranty is nice, but not if it’s basically the same solution (same problem).
If an aftermarket solves the issue, I’d prefer to go that route…

 

[Sandman 4x4]

I’m just glad I went with the automatic. Mostly due to issues posted pertaining with a ratios, especially reverse being too high/fast, not low/slow/precise.

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