Chattering Noise when Accelerating Manual Transmission

[ShadowsPapa]

Thinking through what happens at "about 3,000 RPM" - you drop out of the valve low lift mode and into the intake valve high lift mode.
The valve lash would change during the transition, causing possible excess lash and valve train rattle.
However, it doesn't sound quite like that, either - but with a phone recording that then goes through YT's compression algorthyms and other processes, then gets downloaded to a computer to play via the browser on a computer with less than really hi-fi speakers.......... sounds change.

It's really brief, and sounds too mechanical to be called a ping, rattle is closer to the sound, IMO.

Sponsored

 

[NachoRuby]

Thinking through what happens at "about 3,000 RPM" - you drop out of the valve low lift mode and into the intake valve high lift mode.
The valve lash would change during the transition, causing possible excess lash and valve train rattle.
However, it doesn't sound quite like that, either - but with a phone recording that then goes through YT's compression algorthyms and other processes, then gets downloaded to a computer to play via the browser on a computer with less than really hi-fi speakers.......... sounds change.

It's really brief, and sounds too mechanical to be called a ping, rattle is closer to the sound, IMO.

It's between 2900-3200 when it does it, and going WOT makes it stop. It stop immediately at 3200 rpm, too. Heat mas it worse. I agree with whoever said it was a resonance related to something expanding.

 

[Advntrbound]

My 2020 Sport S with MT and I have the same intermittent rattle. No rhym or reason. I'm thinking something is heating up and expanding causing clearance issues. I tried to attach my gopro under the jeep pointing at the transmission but the gopro won't turn on.

 

[Oldmon]

Thinking through what happens at "about 3,000 RPM" - you drop out of the valve low lift mode and into the intake valve high lift mode.
The valve lash would change during the transition, causing possible excess lash and valve train rattle.
However, it doesn't sound quite like that, either - but with a phone recording that then goes through YT's compression algorthyms and other processes, then gets downloaded to a computer to play via the browser on a computer with less than really hi-fi speakers.......... sounds change.

It's really brief, and sounds too mechanical to be called a ping, rattle is closer to the sound, IMO.

Yes, 100% agree. I believe it's a ressonance-related rattle inside the cabin. It sounds, to me, like it's coming from somewhere on the driver's side in/under the steering column area.

 

[ShadowsPapa]

Yes, 100% agree. I believe it's a ressonance-related rattle inside the cabin. It sounds, to me, like it's coming from somewhere on the driver's side in/under the steering column area.

Your video of it was actually quite good, one of the better examples, IMO.

 

[Oldmon]

I'm at 24k. Good news is it won't get worse. Bad news is it won't get better. Too many other things I like about it to let it really bother me though. I'll keep mentioning it every time I go in for service, and hope that maybe eventually there'll be a resolution.

So far, I'm kind of with you. I've been a Jeep guy for a long time. There are a lot of things I really like about my Gladiator. There aren't a lot of alternatives if you want a manual trans truck with optional roof/doors, of course ?.

With that said, it's kind of unacceptable for a nearly-new $60k vehicle and it's a little embarrassing when other people are in the car. If I'm being honest, I grind my teeth a little bit every time it happens, even when I'm in the car alone (which is most of the time). This is the kind of thing I was willing to live with when I was 18, driving a 10 year old car with 140k miles. I don't know if I'm willing to live with this issue indefinitely, minor as it seems/is.

 

[Oldmon]

Update, I’ve done a lot of trial and error with HVAC settings and it doesn’t seem to make any difference at all. I rode with a friend in his late model JKU Rubicon with the V6 and manual transmission over the weekend and it makes the same sound. He said it’s been doing it forever and it bugs the crap out of him. So I’m going to do some JK searching to see if anybody on that side has figured it out.

I've experimented with the HVAC, as you did, and it didnt notice any changes/impact.

I also had a 2016 V6 Willys JKU with the manual that I bought new. I know it's completely different than the JL/JT, but I never experienced anything like this.

 

[Linkfan03]

Thinking through what happens at "about 3,000 RPM" - you drop out of the valve low lift mode and into the intake valve high lift mode.
The valve lash would change during the transition, causing possible excess lash and valve train rattle.
However, it doesn't sound quite like that, either - but with a phone recording that then goes through YT's compression algorthyms and other processes, then gets downloaded to a computer to play via the browser on a computer with less than really hi-fi speakers.......... sounds change.

It's really brief, and sounds too mechanical to be called a ping, rattle is closer to the sound, IMO.

For me if I lightly press in the clutch (slightly more than needed if it was just the peddle vibrating but not enough to slip the clutch), the rattle goes away. Does that give you any more thoughts about what could be causing the rattle?

Mine used to be crazy consistent when accelerating and spent a total of about 6 months in the shop. Changing the clutch would make the issue go away for about 300 miles and then start back up again. The last attempt was to replace the clutch fork and that has made the issue more intermittent or I'm just lucky/unlucky.

 

[Oldmon]

The thing giving me SOME hope is multiple people are experiencing the EXACT same issue. I know rattles are notoriously hard to source and particularly hard when they are intermittent, but the chattering/rattle you hear in the video from the thread starter isn't similar to the one in the video I posted...it's identical! Same transmission, same engine, happens at exactly the same rpm range, and it's the same (very unique) chattering/rattle sound. Others in the thread are obviously experiencing the EXACT same thing, as well. That, to me, indicates it's probably a design oversight/issue rather than a random one-off type problem. As part of the design, something is routed/bolted/clipped too close to something else in the driver side steering column area and at certain temps/humidity, with the engine under certain load, it's ressonating/vibrating against something else. If we can find the damn thing, we could probably fix it with $.02 of foam ?

 

[NachoRuby]

The thing giving me SOME hope is multiple people are experiencing the EXACT same issue. I know rattles are notoriously hard to source and particularly hard when they are intermittent, but the chattering/rattle you hear in the video from the thread starter isn't similar to the one in the video I posted...it's identical! Same transmission, same engine, happens at exactly the same rpm range, and it's the same (very unique) chattering/rattle sound. Others in the thread are obviously experiencing the EXACT same thing, as well. That, to me, indicates it's probably a design oversight/issue rather than a random one-off type problem. As part of the design, something is routed/bolted/clipped too close to something else in the driver side steering column area and at certain temps/humidity, with the engine under certain load, it's ressonating/vibrating against something else. If we can find the damn thing, we could probably fix it with $.02 of foam ?

It's definitely going to be someone here that finds the source. It's so intermittent that the dealership can never find it.

 

[IanNubbit]

So gonna jump in.

Couple things I can guess here without having the issue myself. Before I even say it though, yes this is something that if covered should be fixed by a dealer, with that being said, if the person who drives the vehicle every day can’t duplicate the issue with any reliability besides some random days at random temps, but definitely this RPM, we (techs) got no chance finding it, so please don’t get mad at your dealer or techor jeep etc., we can’t make magic happen, we want to help, but if you can’t even make the noise happen yourself, we can’t chase something that currently just isn’t there.

okay, now. 1, being manual only, I’m just gonna rule out every engine related possibility, could it be that, yes, but I just don’t think that’s the issue here. What can shake vibrate from the pedal, to the master cylinder, to the bell housing, and in the clutch assembly. Only happening when clutch is engaged, no driveability change or lose of acceleration etc, we can assume we don’t have a internal clutch assembly, throw out bearing, fork or slave cylinder issue. Again, could be, but unlikely. Okay now, line, this is my most likely guess here. There’s multiple clips that hold the line, heat will change the line rigidness and minor changes in diameter. Those metal clips could allow it to rattle with just the right set of conditions. Could just bend each one just a little tighter, and without immediately being under the truck, maybe there’s a routing condition somewhere that’s too tight with not enough rigidity and may need another clamp of some kind. A key spot that this could be very possible but not sure is our issue here is up by the cowl right off the master cylinder. Older models have a quick connect fitting, that was actually part of the recall, on my 22 not sure when it started they completely changed to a thicker rubber line with hose clamps that is much better at staying still. Also just out of the bottom of the master you have the hard line, it’s held extremely close to the firewall heat shield, just minor bend in it from something at some point could cause a rattle here. The last thing is on the pedal at the top, it’s almost the same level as the steering wheel shaft (right at the pivot point for the tilt adjust) so I see where that could be the sound area people are talking about. The link that goes into the master is decently loose on the pedal mount. They changed the design in later models, I know 18 and 19 JLs where I could just tap on the link and it would come off the pedal,the one on my 22 is rock solid, so that could also be an area to inspect as well.

something that’s verrryyyyyyy helpful here is posting your build date/last 8 of your vin/Model Year. I know not everyone’s comfortable posting VINs so build date is good too. That helps track who’s effected. Only post if you are effected though or else everything gets very confusing.

 

[NachoRuby]

So gonna jump in.

Couple things I can guess here without having the issue myself. Before I even say it though, yes this is something that if covered should be fixed by a dealer, with that being said, if the person who drives the vehicle every day can’t duplicate the issue with any reliability besides some random days at random temps, but definitely this RPM, we (techs) got no chance finding it, so please don’t get mad at your dealer or techor jeep etc., we can’t make magic happen, we want to help, but if you can’t even make the noise happen yourself, we can’t chase something that currently just isn’t there.

okay, now. 1, being manual only, I’m just gonna rule out every engine related possibility, could it be that, yes, but I just don’t think that’s the issue here. What can shake vibrate from the pedal, to the master cylinder, to the bell housing, and in the clutch assembly. Only happening when clutch is engaged, no driveability change or lose of acceleration etc, we can assume we don’t have a internal clutch assembly, throw out bearing, fork or slave cylinder issue. Again, could be, but unlikely. Okay now, line, this is my most likely guess here. There’s multiple clips that hold the line, heat will change the line rigidness and minor changes in diameter. Those metal clips could allow it to rattle with just the right set of conditions. Could just bend each one just a little tighter, and without immediately being under the truck, maybe there’s a routing condition somewhere that’s too tight with not enough rigidity and may need another clamp of some kind. A key spot that this could be very possible but not sure is our issue here is up by the cowl right off the master cylinder. Older models have a quick connect fitting, that was actually part of the recall, on my 22 not sure when it started they completely changed to a thicker rubber line with hose clamps that is much better at staying still. Also just out of the bottom of the master you have the hard line, it’s held extremely close to the firewall heat shield, just minor bend in it from something at some point could cause a rattle here. The last thing is on the pedal at the top, it’s almost the same level as the steering wheel shaft (right at the pivot point for the tilt adjust) so I see where that could be the sound area people are talking about. The link that goes into the master is decently loose on the pedal mount. They changed the design in later models, I know 18 and 19 JLs where I could just tap on the link and it would come off the pedal,the one on my 22 is rock solid, so that could also be an area to inspect as well.

something that’s verrryyyyyyy helpful here is posting your build date/last 8 of your vin/Model Year. I know not everyone’s comfortable posting VINs so build date is good too. That helps track who’s effected. Only post if you are effected though or else everything gets very confusing.

Where are you located. I feel like you could really track it down, being a jeep enthusiast, manual driver, and a tech. If you're remotely close, I'd bring it you

 

[IanNubbit]

Where are you located. I feel like you could really track it down, being a jeep enthusiast, manual driver, and a tech. If you're remotely close, I'd bring it you

Depending on what part of PA I might be close. Dealer I’m at is in Swedesboro, I’ll warn you we are BOOKED and loaners are a laughing matter, but always down to do my job lol.

 

[Linkfan03]

So gonna jump in.

Couple things I can guess here without having the issue myself. Before I even say it though, yes this is something that if covered should be fixed by a dealer, with that being said, if the person who drives the vehicle every day can’t duplicate the issue with any reliability besides some random days at random temps, but definitely this RPM, we (techs) got no chance finding it, so please don’t get mad at your dealer or techor jeep etc., we can’t make magic happen, we want to help, but if you can’t even make the noise happen yourself, we can’t chase something that currently just isn’t there.

okay, now. 1, being manual only, I’m just gonna rule out every engine related possibility, could it be that, yes, but I just don’t think that’s the issue here. What can shake vibrate from the pedal, to the master cylinder, to the bell housing, and in the clutch assembly. Only happening when clutch is engaged, no driveability change or lose of acceleration etc, we can assume we don’t have a internal clutch assembly, throw out bearing, fork or slave cylinder issue. Again, could be, but unlikely. Okay now, line, this is my most likely guess here. There’s multiple clips that hold the line, heat will change the line rigidness and minor changes in diameter. Those metal clips could allow it to rattle with just the right set of conditions. Could just bend each one just a little tighter, and without immediately being under the truck, maybe there’s a routing condition somewhere that’s too tight with not enough rigidity and may need another clamp of some kind. A key spot that this could be very possible but not sure is our issue here is up by the cowl right off the master cylinder. Older models have a quick connect fitting, that was actually part of the recall, on my 22 not sure when it started they completely changed to a thicker rubber line with hose clamps that is much better at staying still. Also just out of the bottom of the master you have the hard line, it’s held extremely close to the firewall heat shield, just minor bend in it from something at some point could cause a rattle here. The last thing is on the pedal at the top, it’s almost the same level as the steering wheel shaft (right at the pivot point for the tilt adjust) so I see where that could be the sound area people are talking about. The link that goes into the master is decently loose on the pedal mount. They changed the design in later models, I know 18 and 19 JLs where I could just tap on the link and it would come off the pedal,the one on my 22 is rock solid, so that could also be an area to inspect as well.

something that’s verrryyyyyyy helpful here is posting your build date/last 8 of your vin/Model Year. I know not everyone’s comfortable posting VINs so build date is good too. That helps track who’s effected. Only post if you are effected though or else everything gets very confusing.

VIN for me 1C6JJTBG4LL162043

Just to make sure this also gets seen, mine is pretty consistent and the dealership here has taken it apart and stuck chassis ears on it all over and driven over 600 miles test driving my truck trying to track the source. According to them the sound is coming out from the pedal, but no idea what's causing it (they have replaced my pedal and cylinders twice with no change).

Also of note lightly pressing on the pedal when the rattle is happening (more than if the pedal is vibrating but not enough to slip the clutch) will stop the rattle.

 

[NachoRuby]

VIN for me 1C6JJTBG4LL162043

Just to make sure this also gets seen, mine is pretty consistent and the dealership here has taken it apart and stuck chassis ears on it all over and driven over 600 miles test driving my truck trying to track the source. According to them the sound is coming out from the pedal, but no idea what's causing it (they have replaced my pedal and cylinders twice with no change).

Also of note lightly pressing on the pedal when the rattle is happening (more than if the pedal is vibrating but not enough to slip the clutch) will stop the rattle.

Mine doesn't seem to be coming from the pedal. It seems like the dash. Or steering column.

Sponsored