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Strange "thump" on acceleration


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I've been trying to figure this one out for the past few weeks. When I step on the gas from a stop I get this thump sound from the left wheel and usually the steering wheel will jerk to the left when it thumps. I've tightened the axle nut and lug nuts. Not sure what else could be causing this sound. Oddly if I accel really slow it will not make the sound or jerk the wheel. Anyone had this happen to their EA82? I hope it is something simple. CV's are only 3mo old, so I'm thinking it is suspension related. Any thoughts, thanks! :)

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does this happen at speed? say when cruising a steady speed, and letting off the gas, opposite of what yours is doing. this to me sounds like the DOJ is going bad, the inner side of the axle on the tranny.

 

generally a bad doj will jerk the wheel and you feel it in the wheel either on acceleration or deceleration

 

inspect the axle boots. the doj is fairly easy to service, take apart and clean, inspect and re-boot. once you have it apart you can consider if its useable or not. look for debris if they are present that is your problem, if the races are not chewed up you can re-grease them with moly EP grease (molybendum) and put a new boot and clamp on it

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I've been trying to figure this one out for the past few weeks. When I step on the gas from a stop I get this thump sound from the left wheel and usually the steering wheel will jerk to the left when it thumps. I've tightened the axle nut and lug nuts. Not sure what else could be causing this sound. Oddly if I accel really slow it will not make the sound or jerk the wheel. Anyone had this happen to their EA82? I hope it is something simple. CV's are only 3mo old, so I'm thinking it is suspension related. Any thoughts, thanks! :)

 

I had this exact problem, turned out the bolts that attach the radius arm bracket to the frame were loose, tightened them up and it's gone... It would also clunk if I stop really fast.

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does this happen at speed? say when cruising a steady speed, and letting off the gas, opposite of what yours is doing. this to me sounds like the DOJ is going bad, the inner side of the axle on the tranny.

Miles...when crusing, if I let off the gas nothing, BUT if I jump on the gas(like stab at it), I hear a thud. If I ease into the gas slowly, nothing. I will check the radius arm bolts suggested by presslab. Anyone else? Thanks!

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  • 3 weeks later...
I had this exact problem, turned out the bolts that attach the radius arm bracket to the frame were loose, tightened them up and it's gone... It would also clunk if I stop really fast.

 

UPDATE: I got under the car and tightened the 3 bolts where the radius rod attaches to the frame. Nothing was really loose. I did tighten up the sway bar bolts where it attaches to the lower control arm. That seemed to help a little. Now it dosent always thump on accel. but only once an awhile. What's really strange is that it does it more in the afternoon than in the mornings? As far as the DOJ I squeezed the boot to see if there were any parts laying around in the boot...nope. I would think if it were the DOJ the problem would always be there since it is always rotating. Man, I sure hope it isn't something in the trans! Are there any other possibilities out there? thanks again for the help!

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Check the engine pitch stabilizer bar bushes.

Is that the bar under the spare tire? If it is, I tightened those bolts as well. If not could you point me in the right direction? Would worn stabilizer bar bushings cause this thumping to occur? Thanks all... :banghead:

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Is that the bar under the spare tire? If it is, I tightened those bolts as well. If not could you point me in the right direction? Would worn stabilizer bar bushings cause this thumping to occur?

 

If you changed it by tightening your sway bar bolts, then you are going in the right direction - I would make sure that all the rubber sway bar (stableizer) bushings are in good shape. - it could theoretically cause a clunk

 

how about balljoints? are they in good shape? - jack the front end up (front tires off the ground) and see how much free motion is in the suspension

 

Have you checked your AT fluid level? A thunk on hard acceleration can also be a sign of a torque converter having issues.

 

If it is 4WD, a bad U-joint can also clunk (it is impelled even when you are not in 4WD mode)

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