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Knock noise on acceleration from stop

Rogue321

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I've been trying to figure this out. One dealer said it was brakes pads and rotors. I don't use that dealer anymore. I have another one with appointment on August 12th.

It's a knocking noise from a stop. Most of the time it's in the rear. Sometimes it's from the front. Or at least, seemingly. It tends to do it more often on a hill. I've checked for loose nuts and bolts on suspension. Didn't retorque, but it's all plenty tight. Bushings appear fine by sight.

In the video, when you hear the noise, sometimes the dif breather tube jiggles. Then at :54, the entire drive shaft jerks abruptly on the second pop.

I've seen this issue mentioned on several forms but with no resolution.

Anyone experience this?

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Motoristx

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I have this going on with my Jeep.

It knocks with both the braking and acceleration. One or more of the links is loose in the suspension. For me, I have some after market parts like skids on the rear lower shock mounts, and I Have a bad bushing in my front track bar. What I did park it on a level surface, not my driveway since is slopes slightly, and put it in park. The trick is to not have any pressure on the components that might prevent you from feeling the slack. Then I jiggled everything till I found the culprit.

My front Track bar bushing at the frame is bad. I found this by having someone slightly jerk the wheel back and forth while observing all of the components in the front. I basically looked at every place the front axle is connected. Both Lower control arm joints bolt up places axle and frame, Both Uppers axel and frame, and both ends of the track bar. While doing this I found a loose connection at the lowers and axle, which I fixed by tightening, and the bad bushing, which will be replaced soon.

For the rear I just had to jiggle everything, and use a medium sized flathead screwdriver the gently pry between the Bushings and frame/axle mounts. I found my skids on my lower shock mounts need an extra shim in them to help the clamping force on the rear Lower control arms. I couldn't find this while parked in the driveway because of the slope the driveway had put pressure on the "loose" components.

Good luck, I hope this helps.

Also, What I found is some of these brackets have square holes, and use round bolts. That doesn't help because it will eventually wallow out the bolt holes on the brackets making them a larger diameter than the bolt, increasing the diameter making them looser.
 
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Rogue321

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I have this going on with my Jeep.

It knocks with both the braking and acceleration. One or more of the links is loose in the suspension. For me, I have some after market parts like skids on the rear lower shock mounts, and I Have a bad bushing in my front track bar. What I did park it on a level surface, not my driveway since is slopes slightly, and put it in park. The trick is to not have any pressure on the components that might prevent you from feeling the slack. Then I jiggled everything till I found the culprit.

My front Track bar bushing at the frame is bad. I found this by having someone slightly jerk the wheel back and forth while observing all of the components in the front. I basically looked at every place the front axle is connected. Both Lower control arm joints bolt up places axle and frame, Both Uppers axel and frame, and both ends of the track bar. While doing this I found a loose connection at the lowers and axle, which I fixed by tightening, and the bad bushing, which will be replaced soon.

For the rear I just had to jiggle everything, and use a medium sized flathead screwdriver the gently pry between the Bushings and frame/axle mounts. I found my skids on my lower shock mounts need an extra shim in them to help the clamping force on the rear Lower control arms. I couldn't find this while parked in the driveway because of the slope the driveway had put pressure on the "loose" components.

Good luck, I hope this helps.

Also, What I found is some of these brackets have square holes, and use round bolts. That doesn't help because it will eventually wallow out the bolt holes on the brackets making them a larger diameter than the bolt, increasing the diameter making them looser.
Thanks.

I did check all the rear components (since it mostly comes from there). Checked that the bolts were tight and wiggled things. I didn't see anything out of sorts. I haven't checked the front yet.

I'll check it again this weekend with a decent sized screwdriver to see if I can find the culprit.
 

Motoristx

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I thought about it some more. My ball joints actually wore out prematurely. It would also be a good idea to jack up the front axle, and push/pull the top of the wheels to check for bad ball joints. Mine wore out in 8K miles, and I had them replaced with the rebuild able Dynatrac ball joints. It took 2 people to check mine. One push/pulled while I looked for looseness.

Sure could have been done under warranty, but i didn't want to have to deal with it again.
 

Jrods_sport_S

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I've been trying to figure this out. One dealer said it was brakes pads and rotors. I don't use that dealer anymore. I have another one with appointment on August 12th.

It's a knocking noise from a stop. Most of the time it's in the rear. Sometimes it's from the front. Or at least, seemingly. It tends to do it more often on a hill. I've checked for loose nuts and bolts on suspension. Didn't retorque, but it's all plenty tight. Bushings appear fine by sight.

In the video, when you hear the noise, sometimes the dif breather tube jiggles. Then at :54, the entire drive shaft jerks abruptly on the second pop.

I've seen this issue mentioned on several forms but with no resolution.

Anyone experience this?

Hey Rogue321. Did you figure it out? I’m experiencing the same and it’s driving me crazy.
 

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gek

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My wife's was doing something similar. If it is in park and I pushed on it I could recreate it. Seemed like it had excessive backlash. Took it in and they found that it did have excessive backlash and they replaced all the bearings in the rear end and ordered a new carrier under the powertrain warranty.
 
 



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