Rattling upon acceleration

xpsruler

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I originally wrote about this in the engine forum but I'm thinking this may possibly be a transmission problem.

I've noticed recently my Jeep makes a gurgle/rattling noise when accelerating that can be heard from the outside as well as the inside if the windows are down. I was concerned about possible engine knock but use 87 octane per the manual and it has only started recently. It also seems strange that it most noticeably happens when accelerating in 3rd gear (auto transmission but my display tells the current gear).
The noise definitely is louder when going uphill as well.

Another thing that has me concerned it may be the transmission is that the noise does not happen if the gas pedal is pressed while in neutral.

Has anyone else experienced anything like this or know what this noise may be? I'm not super happy cause if its the transmission who knows how long I'll be without it if it needs work... My Jeep is already gonna be in for about 2 weeks of shop time for hail damage as well:mad:.

On the bright side my previous two issues appear to be resolved for now. After finding about 20 fuses that didnt seem fully seated and seating them, my ess has been working and I haven't recieved error codes. The clicking from the suspension when turning has gone away on its own (hopefully for good) as well.

Just needed to vent a bit but if anyone has any ideas what this may be or have any advice I'm open ears. Thanks!



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JoshH

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My Jeep just started making a similar noise, almost like an exhaust leak or vacuum leak maybe, but only while acceleration. It seams to be coming from the front drivers side of the cabin thou. Have you had any luck figuring it out?
 

JeepCares

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Hi guys,

If you decide to have this looked at by the dealer, our team is always happy to assist with the servicing process. We're available via direct message and would need your VIN to get started.

Jasmine
Jeep Social Care Specialist
 

subiescott77

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If you're for a JLUR, check your Bfgoodrich KO2s for rocks jammed in the tread. That and there is a label attached to the front driver side coil in the wheel well that flaps .
 

wranglerguyman

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I noticed this too. It's very faint, but if you're on the highway driving next to a divider, you can hear the rattle. I had a similar sound coming from an older car of mine, and it turned out it was the heat shield for the catalytic converters. Not sure if it's the same thing here.
 

subiescott77

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After I cleared rocks out of my tires I didn't hear anything anymore but I'm not really worried about it unless it gets worse.
 

JimL

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This also occurs in 4th gear, about half throttle accel at 40 mph, or so. 4th gear on the manual is direct drive, so that pretty much rules out something like countershaft bearing lash or any of the gears. The growl/rattle sounds like it might be in the 100-120 Hertz range. There is typically some type of dampening in a clutch disc center. If the frequency of the rattle matches 3 times the crankshaft rotation frequency, it would mean we are hearing the stack-up of drivetrain lash. Unfortunately, my FFT Spectrum Analyzer on my iPad is too crude to separate the various frequencies, and it has no raster function that I could use to identify onset of the frequency my ears hear.

Driveline normal lash can be tricky to quiet, because there are things like hollow driveshaft tubes that love to "ring" if conditions are right. I remember field testing some "cored" driveshafts for small pickups. They were very quiet, but durability of the fill material was suspect and the drveshafts were heavier than original. That can lead to other long term issues and they have never seen much use in the industry. The super quiet drveshaft designs used in luxury cars are not a solution for off-road work....spinning bits with rubber components and tight clearance centering.....not something to bounce off a rock or log!

My 16 year old Tracker manual trans car has similar noise AND it has loud rattle with the clutch engaged in neutral at idle. The clutch damping is certainly loose and worn out on the old car, so not a surprise. That trans has all its gears rattling that are NOT loaded, due to the worn out clutch dampers.

Does anyone know what type damping is used in our clutch? Springs, or rubber blocks, or sprung two piece flywheel? Those flywheels were used in a few cars that had solid center clutch disc....I would be really surprised if somebody tried that one again.....they caused a lot of wrong warranty expense!

JimL
 
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xpsruler

xpsruler

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This also occurs in 4th gear, about half throttle accel at 40 mph, or so. 4th gear on the manual is direct drive, so that pretty much rules out something like countershaft bearing lash or any of the gears. The growl/rattle sounds like it might be in the 100-120 Hertz range. There is typically some type of dampening in a clutch disc center. If the frequency of the rattle matches 3 times the crankshaft rotation frequency, it would mean we are hearing the stack-up of drivetrain lash. Unfortunately, my FFT Spectrum Analyzer on my iPad is too crude to separate the various frequencies, and it has no raster function that I could use to identify onset of the frequency my ears hear.

Driveline normal lash can be tricky to quiet, because there are things like hollow driveshaft tubes that love to "ring" if conditions are right. I remember field testing some "cored" driveshafts for small pickups. They were very quiet, but durability of the fill material was suspect and the drveshafts were heavier than original. That can lead to other long term issues and they have never seen much use in the industry. The super quiet drveshaft designs used in luxury cars are not a solution for off-road work....spinning bits with rubber components and tight clearance centering.....not something to bounce off a rock or log!

My 16 year old Tracker manual trans car has similar noise AND it has loud rattle with the clutch engaged in neutral at idle. The clutch damping is certainly loose and worn out on the old car, so not a surprise. That trans has all its gears rattling that are NOT loaded, due to the worn out clutch dampers.

Does anyone know what type damping is used in our clutch? Springs, or rubber blocks, or sprung two piece flywheel? Those flywheels were used in a few cars that had solid center clutch disc....I would be really surprised if somebody tried that one again.....they caused a lot of wrong warranty expense!

JimL
4th gear is where I notice it as well. I'll be honest and say I'm not familiar with a lot of the terms you mentioned but found it interesting. I can live with the noise but is it causing any damage you think?
 
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xpsruler

xpsruler

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Was able to record it. Any ideas?
 

iflyimpilot

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Noticing this same noise on mine too -- JLU Sport. Seems to happen when accelerating under load in a higher gear and lower RPM. I've noticed it too when going around 20-25mph with light gas pedal and sometimes while letting off. Did a ton of research and I'm getting confused on whether it's exhaust related (e.g. heat shield rattle) or even something like pre-ignition or spark/engine knock. Watching this thread and hoping we can get some answers!
 
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xpsruler

xpsruler

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Noticing this same noise on mine too -- JLU Sport. Seems to happen when accelerating under load in a higher gear and lower RPM. I've noticed it too when going around 20-25mph with light gas pedal and sometimes while letting off. Did a ton of research and I'm getting confused on whether it's exhaust related (e.g. heat shield rattle) or even something like pre-ignition or spark/engine knock. Watching this thread and hoping we can get some answers!
Mines at the shop still but I really hope they can solve it.
 

CZ 75

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My case manager basically said to run higher octane and inform them again if it worked before my next service at the dealer.

At this point they don't know what to do. If higher octane fixes it or not then maybe it narrows down what they need to address.
 

iflyimpilot

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My case manager basically said to run higher octane and inform them again if it worked before my next service at the dealer.

At this point they don't know what to do. If higher octane fixes it or not then maybe it narrows down what they need to address.
Did they mention anything about preignition prior to suggesting trying to run a higher octane? Also did they try to replicate the noise so they could hear what you were talking about?
 

CZ 75

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Did they mention anything about preignition prior to suggesting trying to run a higher octane? Also did they try to replicate the noise so they could hear what you were talking about?
Yes the tech also heard it and agreed it was knock. I had to drive it with the tech inside in order for them to hear it.
 








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