Chattering Noise when Accelerating Manual Transmission

[jeepobx]

I’ve noticed this while driving up steep and windy mountain roads. Usually when accelerating at 3000rpm. But not every time.

Pushing up from underneath the clutch pedal seems to deaden the rattle for me.

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[ruggburnout]

I can be added to this list for the chattering noise. Started noticing it in the past 4000-5000 miles and I'm just under 24K miles now. Rubicon MT built in June 2021.

I consistently get the noise around 3000 rpm and it is most apparent in 2nd gear, but due to vehicle speed/wind noise/road noise not being as loud as 3rd, 4th, etc. The noise path is definitely heard at the dash/steering wheel so no idea where the source is.

I'm not bothering to take it to a dealership until the source is determined as this looks to be a common issue. I don't want the problems that result from taking things apart trying to find the source. I would prefer they find it on another vehicle.

 

[be77solo]

Just reporting in, hadn't seen this thread before, but mines been doing this exact noise when accelerating through ~3000RPM as well. Sounds exactly like the videos and as everyone is describing, though mine seems more dash/steering wheel/that part of firewall area to me and haven't noticed the clutch having anything to do with it. Even have an appointment with the dealer to have the noise fixed and a leaking rear shock replaced next week. I assumed it was just a heat shield or something that was loose or vibrating around the firewall area in that RPM range.

BUT, now having read this thread I'm not too hopeful the dealer will find anything.

It's the same as others. I get it when accelerating both fairly aggressively or more chill, and it's consistently right in that 2900-3600ish RPM range, in any gear, but most noticeable in 2nd or 3rd. When accelerating more aggressively, my foot is lightly on the clutch (not depressed, fully engaged) so touching it with my foot doesn't stop the noise like some have reported.

I've got a '21 Willys Sport 6MT I bought last May (where do I find build date?), just turned 10K miles. Been making the noise fairly consistently for the last ~3K miles or so.

And like others that have it has said, it's pretty annoying and not just a Jeep thing ha... I honestly assumed I was about to lose a heat shield somewhere when I first heard it, but upon looking it over, nothing was loose or out of place.

I'll report back what the dealer says next week, and if anyone has any more progress with this would love to hear it.

@JeepCares , any progress on your side with this issue before I head to dealer?

 

[ShadowsPapa]

I've got a '21 Willys Sport 6MT I bought last May (where do I find build date?), just turned 10K miles. Been making the noise fairly consistently for the last ~3K miles or so.

Build date is on a sticker on the door jamb.
You'll find the year and month, but if you look for the MDH, that indicates the Month, day of the month and hour it was built.
So you can get the year, month, day of the month, and hour from that sticker.

MDH of 051520 would be May 15th, 20th hour (8pm)

 

[be77solo]

Build date is on a sticker on the door jamb.
You'll find the year and month, but if you look for the MDH, that indicates the Month, day of the month and hour it was built.
So you can get the year, month, day of the month, and hour from that sticker.

MDH of 051520 would be May 15th, 20th hour (8pm)

Good to know, thanks!

So mine's a '21, built Feb 5th 2021 @ 19:00

 

[ShadowsPapa]

It would take a ton of work, but too bad someone with the manual transmission hasn't taken one of those small "backup cameras" - the wireless kind, and placed it in various spots up under the dash, around linkage, and then in the engine bay around the area of the steering column.
It would have to be someone on vacation, retired, young, agile, and with nothing better to do LOL
But you'd need to see it if it's harmonics - the speed and load of the engine at specific points causing something to vibrate.
The effect was an accident. George struck a short/muted A note and it caused feedback on the guitar amp - some say after he let up on the string.

 

[ruggburnout]

So I've been trying a few things to try to figure out the source... The noise is consistent for me. I rev'd the motor to 3000rpm sitting in neutral, clutch pedal not depressed and the noise is still there. it seems like it is quieter but can hear it around 2000rpm and it gets louder as I get up to the 3000rpm range. This is making me think it is either engine, flywheel, engine mount, etc...

Has anyone else tried to see if they can reproduce the noise at a stop and revving the motor in neutral?

One thought I didn't try is to see if revving while depressing the clutch pedal changes anything. Since I can reproduce at a stop, I will see if I can figure out anything under the hood.

 

[ruggburnout]

Update on my chatter noise. I had camshaft high lift lobe/follower wear. Both intake camshafts and all followers were replaced. I pick up my Jeep next Monday.

The noise I had was very similar to a few posted on this thread, so I think this may be the issue.

 

[onewhippedpuppy]

Update on my chatter noise. I had camshaft high lift lobe/follower wear. Both intake camshafts and all followers were replaced. I pick up my Jeep next Monday.

The noise I had was very similar to a few posted on this thread, so I think this may be the issue.

Please keep us posted on if the noise is gone after the work is done.

 

[ruggburnout]

Please keep us posted on if the noise is gone after the work is done.

It was definitely the issue. High lift lobe on one follower was worn. Camshaft was still installed so I couldn't see the follower wear, but I'm sure it also has wear on the coating. Mechanic said he has seen many Pentastar Upgrade engines with this issue.

 

[onewhippedpuppy]

So I’m assuming you have your JT back now, did the noise go away?

 

[BuyHold]

So I’m assuming you have your JT back now, did the noise go away?

@ruggburnout

Please let us know. I would find it interesting if this were the culprit because the issue appears to be isolated to 6sp MTs. Last time I checked there are far more pentastars in AT models and haven't heard of this issue on those. That said, this is the first time I have heard of this in MTs though I experienced this exact same thing just this last summer. I thought it was the clutch or something vibrating just behind the firewall (wasn't clear).

manual transmission, ~3000 rpm, 3rd gear, uphill, hot engine, hot weather, chattering occurred.

I have a 21 JLR built in Jan 21.

 

[ruggburnout]

@ruggburnout

Please let us know. I would find it interesting if this were the culprit because the issue appears to be isolated to 6sp MTs. Last time I checked there are far more pentastars in AT models and haven't heard of this issue on those. That said, this is the first time I have heard of this in MTs though I experienced this exact same thing just this last summer. I thought it was the clutch or something vibrating just behind the firewall (wasn't clear).

manual transmission, ~3000 rpm, 3rd gear, uphill, hot engine, hot weather, chattering occurred.

I have a 21 JLR built in Jan 21.

So good news and bad news.... sorry it is long winded.

Good news, I picked up the JT on November 28 and the noise was gone. Everything working great.

A bit unrelated to the actual repair, I didn't like a few things the Service Advisor did during the repair (i.e. rental car, communication) so I gave a semi-bad review. He didn't like that and let me know by calling me repeatedly while I was at a work Christmas party... When I answered finally because I didn't recognize the number with the persistent calling, he bitched me out for the review.

The Service Manager called me about a week later and I explained the reasons for the review. I let him know about the unprofessional behavior from the Service Advisor after the review. I also mentioned my concerns with the metal debris from worn cam lobe... and that the oil wasn't changed after the repair which to me would make sense.

The next few weeks all continued to be well. All my driving was local between 3 mile trips to maybe 20 miles max. No noise issues.

My first extended trip last Tuesday for the Christmas holiday is where the news goes bad. I was driving from Detroit to Pittsburgh which is 300 miles. All freeway driving and mostly Turnpike. About three hours and 200 miles in, I get a CEL and go into limp mode. I drove about 5 miles or so to the next Service area and filled up on gas. I have a bluetooth OBD reader, so I pulled the code which was P0390 (bank 2 cam position sensor B) which is the exhaust cam... This is the bank with the replaced camshaft and all followers. I did some key cycles and got out of limp mode... or so I though. I got back on the Turnpike and went right back into limp mode. I drove maybe another 10-15 miles and finally pulled over where it was a bit safer... not directly on the shoulder. I read the codes again and got P0306 (cylinder 6 misfire) on top of the P0390. At this point the engine was running rough so I wasn't going to push it any further.

I called Roadside Assistance figuring a tow would be free since it is under warranty... I was wrong. Since I wanted it towed to a dealership near my destination in Pittsburgh, it would have been $400. Luckily, I have AAA so I got it towed for free though it took two tow trucks and 4 hours since I was on the Turnpike. Getting home at 1 am... fun!

Dealership in Pittsburgh called me next morning. Right off the bat from the notes I left about the potential cause, Service Advisor said I would have to pay if the damage is from workmanship of the previous repair because warranty doesn't cover mistakes in repairs. He also said they wouldn't be able to look at it until Jan 3 at best... and of course I need to head back to Detroit Jan 1. To top it off... he said we don't have loaners and don't do rental cars.

I called Chrysler Customer Assistance and explained the workmanship comment, when they can work on it, and the no loaner/rental car. A case was opened and the Case Manager called the dealership. I can live without the loaner for now as I can use my Dad's Jeep. I called the dealership that did the initial repair and emailed the Service Manager letting him know that this happened and it probably was caused by something they did. Of course... no return calls or messages from them. I am 100% done with Suburban CDJR in Troy, MI.

Friday, Service Advisor from Three Rivers CDJR called me. I told him the work completed at Suburban and what they replaced because he couldn't get a hold of them either. The Case Manager was able to get Three Rivers authorized to do the repair under warranty (as it should be of course). Mechanic opens up left bank valve cover and lo and behold finds the new intake camshaft cracked in half because the cam cap bolts were not tightened. They replaced the camshaft, re-tapped the cam cap hole, and replaced the bolt. Service Advisor said it is working now. Mechanic thinks the right side is maybe making some noise though. Suburban did replace all the followers on the right bank, but not the camshaft (which I thought was dumb). So it is possible, that he didn't torque the cam cap bolts on that side as well.

Of course, mechanic is on vacation until Jan 2, so the right side work won't be done until then. I am concerned about this last failure and any debris from the initial issue and now the broken camshaft. I started pushing for a new engine, but sounds like that won't happen. I will push Customer Assistance to give me an extended powertrain warranty with these issues... especially with the second issue being frankly from negligence.

Conclusion, noise was gone from replaced intake camshaft and followers but Suburban CDJR in Troy, MI is not a place to trust that repair work will be done correctly.

I'll keep you posted on results after the repair is completed.

 

[ruggburnout]

@ruggburnout

Please let us know. I would find it interesting if this were the culprit because the issue appears to be isolated to 6sp MTs. Last time I checked there are far more pentastars in AT models and haven't heard of this issue on those. That said, this is the first time I have heard of this in MTs though I experienced this exact same thing just this last summer. I thought it was the clutch or something vibrating just behind the firewall (wasn't clear).

manual transmission, ~3000 rpm, 3rd gear, uphill, hot engine, hot weather, chattering occurred.

I have a 21 JLR built in Jan 21.

To also answer your questions... This is an issue on all Pentastar Upgrade Engines. On all Chrysler vehicles. Doesn't matter what transmission either.

I want to say the take rate on Wranglers and Gladiators with manuals is probably under 20%. It was 30% on Wranglers about 8-10 years ago, but less and less people are getting manuals in the US. I worked in the Manual Transmission group at Chrysler from 2012-2015 and did some of the initial development work on sourcing this current Aisin transmission... but don't blame me for the problems ... Management didn't listen to anything I suggested and the reason I left the group.

My thoughts on why vehicles with manuals seem to hear this noise more... Automatic shift points are probably not getting into the 3000+ rpm for very long or at least long enough to notice the noise. With the manual, you are controlling the shift points and will definitely sit in the 3000-4000 rpm range where the noise is most clearly heard. I found the only time I really heard it while driving was 2nd gear starting around maybe 2500 rpm up to maybe 4500 rpm. First gear is revved out so fast that I could never really fully discern the noise. Second gear doesn't have the road and wind noise, so the noise stands out. Third gear and beyond, the road and wind noise pretty much drown it out.

Best test is to rev the engine in neutral somewhere quiet. Even better if you pull up to a brick wall, where all the noises get amplified by bouncing off the hard surfaces. This would work with automatics too.

The mechanic at Suburban CDJR told me he sees this camshaft wear problem most on Grand Cherokees (all automatics), but pretty much on all vehicles. He did say my mileage (23700) was probably the lowest he had seen though.

 

[onewhippedpuppy]

You basically summarized the biggest reason I haven’t been back to my local dealer despite the persistent engine noise and the occasional squeak from my Mojave shocks. People love having a warranty but when the techs doing the work are inept and indifferent it’s a lot harder to bite that bullet. Even worse when most dealerships don’t support warranty repairs with a loaner, which is damn near unheard of.

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