Chattering Noise when Accelerating Manual Transmission

[Linkfan03]

Hi All,

The noise occurs when accelerating in the 3k-3.5k RPM range after the transmission is warmed up. I need to drive 5-10 miles, letting the engine warm up isn't enough to replicate the issue.

Here is a video of me recreating the issue: https://photos.app.goo.gl/umvvwU7BFWdwWPDU7

The noise goes away if you lightly press in the clutch (not enough to slip the clutch, but more than if just the pedal was vibrating).

I have been plagued with this issue since the truck had about 2,000 miles on it. Everything has been replaced from the clutch pedal to the entire transmission assembly. The only repairs that have made the noise disappear temporarily was when the clutch, clutch release bearing, and the slave cylinder were all replaced together. That repair has been made twice (the second time the flywheel was also replaced in hopes replacing it all together would keep it from coming back) and it only lasts for about 200 miles.

I have tried higher octane gas with no luck either.

I found this post which matches my noise exactly.

Mines been doing it since 3k miles. The dealer couldn't find the issue. The sound is getting really anoying.

The service manager is stumped at this point, and the corporate mechanic didn't have any luck in diagnosing the issue either. Any thoughts or ideas would be appreciated.

Thank you in advance!

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[mojocho]

Following. Mine started over the winter but was intermittent. Took it to the dealer but that day it decided not to make the noise so nothing has been done.

The last week it's gotten significantly worse/louder. All gears at 3k rpm. Going to try to take it in this weekend again. Happens in all gears at same RPM. Less noticeable in 4th and 5th mainly because the road and tire noise overcome it.

'20 Rubicon manual with 46k miles

 

[NachoRuby]

Seems to be an ongoing issue many of us are having, with no resolution, and dealer hasn't been able to recreate. Mine has been doing it intermittently since 2,300 miles. I'm at 20,000 miles so far, so I guess it's just a noise. ¯\_(ツ)_/¯. It's discussed in detail in another thread. Thus far, it has not caused anyone any issues, but it's annoying, and too infrequent to diagnose.

Here is the main thread where we've been talking about it.

https://www.jeepgladiatorforum.com/forum/threads/manual-transmission-club.17084/post-908862

 

[Linkfan03]

Mine happens every acceleration in 3k-3.5k RPM range after driving the truck for 4-5 miles. My video was after the noise returned after replacing the clutch, release bearing, and slave cylinder, so it was much quieter.

At it's worst it will drown out the stereo.

I looked at all the threads I could find talking about noises and couldn't find any that matched this exactly except for the quoted video. Do you have a link?

 

[NachoRuby]

Mine happens every acceleration in 3k-3.5k RPM range after driving the truck for 4-5 miles. My video was after the noise returned after replacing the clutch, release bearing, and slave cylinder, so it was much quieter.

At it's worst it will drown out the stereo.

I looked at all the threads I could find talking about noises and couldn't find any that matched this exactly except for the quoted video. Do you have a link?

Starting about here. But none of us have gotten anywhere with it yet.

Mine does it occasionally from about 2800 to 3200 rpm, and it sounds like a vibration. It stops at around 3200, and isn't loud enough to drown out the stereo.

This post:
https://www.jeepgladiatorforum.com/forum/threads/manual-transmission-club.17084/post-644349

This post:
https://www.jeepgladiatorforum.com/forum/threads/manual-transmission-club.17084/post-645881

Several more in that thread.

 

[NachoRuby]

I think I'm going to try to compile all the posts, and then send something to @JeepCares. It just seems like individual dealerships aren't able to figure it out, even if they can hear it, since it's so intermittent. If all the noise complaints are in one place, maybe they can see that it's a connected issue, and get engineering involved at a corporate level, and we could get a TSB. I love my manual, but that noise is the one thing I don't like.

Unfortunately (or fortunately) since no one's engine or transmission has failed from it, there hasn't been a teardown for anyone, so the source hasn't been located. I think it's just an annoyance, but it's a major one at times.

 

[JeepCares]

Hi, all. We see we are tagged, and we're here to help.

Anyone that has a dealer appointment scheduled or is at the dealer, please send our team a private message and we can support you while there. We thank you for bringing this to our attention and look forward to assisting.

Kate
Jeep Cares

 

[gmcul8r]

Not much help, but I have the same exact issue. Always around 3K RPMS, loud rattle, inconsistent on when it happens. 6MT w/ 14K miles

 

[LiftedrubiconJT]

Anyone get this issue fixed? I have an automatic and Mine sounds similar to this. It’s gotten worse now and does it in lower rpm’s. In the beginning only happened around 3k rpm. I thought it was my motor but now I’m thinking it’s the transmission

 

[SelfmodJT]

That video sounds like when the vtec kicks in at the higher rpms in a honda vtec engine. I dont think that is pinging from the engine.

 

[81Mojave]

Anyone rev it while on a lift with someone looking up?
could it be a hard line vibrating against transmission housing?
im hoping it’s not the clutch pressure plate ( not sure how this one is set up)
I haven’t heard it from mine yet, fingers crossed tho

 

[onewhippedpuppy]

Just wanted to chime in that I’m experiencing the same issue, 2021 Mojave 6MT with almost 20k. Started a little after 10k, took it into my dealer but they couldn’t duplicate it. I never notice it with short trips, only longer drives and it seems more frequent when it’s hot outside. Very annoying.

 

[NachoRuby]

Just wanted to chime in that I’m experiencing the same issue, 2021 Mojave 6MT with almost 20k. Started a little after 10k, took it into my dealer but they couldn’t duplicate it. I never notice it with short trips, only longer drives and it seems more frequent when it’s hot outside. Very annoying.

Mine's been doing it on and off since 2500 miles. Never gotten worse, and not all the time. Just every now and then. This is about my only complaint with the vehicle. I'm at 22,000 now. I'll bring it up again at next service. I have it on video. It never does it while I'm at the dealership, though.

 

[ShadowsPapa]

What I'm seeing is that it's annoying, but not a real issue of something broken or breaking in many cases.
Perhaps it's just annoying because people have an expectation based on other vehicles?
And when a manual transmission is involved, I have some ideas there but normally get push back "I know how to drive and have been driving sticks since 1919"

These are very different, though......... torque and power curve and range, gear ratios and so on.
And the engine isn't a Ford, isn't a Chevy LS, whatever. So to say because others don't do it so this one shouldn't isn't really fair or even a valid comparison.

If it's not frequent, happens mostly in hot weather, has not gotten worse............
But then for me to truly judge, I'd have to actually hear it. Videos taken by phone distort frequencies and tend to pick up other sounds, then to reproduce them across the web on different devices......... I've heard recorded "engine rattles" that IMO sounded horrible on video, but in person were something I'd personally not worry much about.

Just some things to think about or chew on a bit.


This is from a GM engineer - one of the brains behind the Northstar engine ->

He also explains here why my 70 390 that did have some detonation when hot didn't suffer any damage - the HP output was under 1:1 - it was less than 1 HP per cubic inch.
My 73 360 doesn't appear to detonate (would I really hear it with the headers? LOL)
It's putting out a bit over 1 HP per cubic inch (377 hp out of a 360)

So - is what people are hearing truly a problem, or just annoying?
And is it annoying because their other vehicles never did it?
How severe, under what conditions? Accelerating at lower RPM with a stick?

 

[JeepCares]

Just wanted to chime in that I’m experiencing the same issue, 2021 Mojave 6MT with almost 20k. Started a little after 10k, took it into my dealer but they couldn’t duplicate it. I never notice it with short trips, only longer drives and it seems more frequent when it’s hot outside. Very annoying.

Mine's been doing it on and off since 2500 miles. Never gotten worse, and not all the time. Just every now and then. This is about my only complaint with the vehicle. I'm at 22,000 now. I'll bring it up again at next service. I have it on video. It never does it while I'm at the dealership, though.

Hey, onewhippedpuppy and NachoRuby. If either of you end up visiting your dealership and need extra support, we're here to help. Separately private message our team at anytime to get started.

Kate
Jeep Cares

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