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MuffinSpecial 07-24-2014 07:56 PM

so my car has started doing a very weird thing. when i accelerate in lets say 3rd gear and let off the gas at around 3500 rpm the rear end sways to the left and when i accelerate it goes to the right. it is way more prevalent wile letting off the gas. i have just installed a set of SR lower control arms a little over a month ago and the issue has started a few days ago. i had a tech were i work and my shop that i go to look at the car and they dont know what the issue is also when you give a sudden punch of throttle you hear a big clunk from the rear on the right side and my mechanic thinks the clunk is the problem but he said everything is nice and tight under the car. when the clunk is hear the issue is more obvious. u have no idea what the issue is and i need help asap the car is not safe drive faster than 80 and thats no fun. its also a very annoying sensation. Car pulls right when you let off and left when you floor it. if anyone has any ideas please help because it is driving my mechanic crazy lol. thanks

2005Redfire6 07-24-2014 08:08 PM

Well the panhard bar controls the left/right motion of the axle, I'd be sure that is secure/installed correctly.

Rudolph Hucker 07-24-2014 11:03 PM

will be worn bushes somewhere on the back axel

MuffinSpecial 07-25-2014 08:41 AM

panhard is good they checked that and tightened it it. the clunk is from the back left and that seems to be the cause of the problem. car has 108k on it so something being worn is easily viable. the question is what. it feels like when you accelerate the clunk is something moving backwards into place. and its loud. if its some bushing it seems like it would be totally shot and the mechanic checked everything and said it all looks tight and i couldnt find anything either. we went at the bushings with a crow bar to see if any of them moved and nothing to be found. all i saw was how bad the stock panhard bar is cuz it flexes so easily lol. im thinking of having them take apart some of the left rear end and see what we can find as far as bushings go.

bl817 07-25-2014 09:46 AM

have you checked the upper control arm above the rear diff? its mounted to the top of the pumpkin with a rubber bushing and then mounted to the body with a bracket under the back seat. if that's worn then your pinion angle will change upon acceleration and deceleration. just a thought. lower control arms keep axle from moving fore and aft, panhard bar is left and right, and upper keeps from rolling fore and aft and keeps pinion angle set. mount a gopro cam under the car facing the rear axle and take for a drive and see what happens. don't think a broke spring would cause car to pull to one side or the other.

Simon1 07-25-2014 10:06 AM

I had that happening and it was my differential. But mine was a Detroit locker.

I also had it happen another time and I had broken all my motor mount bolts.

Maybe find a shop with a chassis dyno and put it on with a camera or someone watching it while you accelerate and decelerate.

MuffinSpecial 07-25-2014 10:07 AM

i was going to try the gopro after work tonight to see if i can see it. im gunna have it look at the left half of the suspension and then the control arm to see if anything is prevalent. if not then im bringing it to the shop to have them start tearing down some pieces

MuffinSpecial 07-25-2014 12:17 PM

im ditching this car for a 15 when it comes out so spending a lot of money on it is not really in my agenda. im gunna go with the gopro after work and see if i can see it. mentioned to my mechanic the diff but we dont think its that. the upper control arm is something that sounds viable but also the clunk sounds like its on the left of the rear end so im confused as of now until i get an eye under there.

LordRipberger 07-26-2014 06:25 AM

What about the brakes? Is is possible you pitched a line or cause some damage while working under there that the right side is constantly braking and is being overpowered when accelerating? So only when power is not being given to the wheels, it is actually braking.

I would imagine though you would smell something so this is probably not it, just thinking out loud.

MuffinSpecial 07-26-2014 07:32 AM

i dont think it is the brake. what ever the clunk is is the issue. the car only pulls like that when you hear the clunk when you accelerate. you have to accelerate hard enough to hear the clunk and then when you let off what ever the clunk is must move back cuz then the rear shakes then lines back up and only shake initially when you let off then its fine. but when you accelerate you can tell after the clunk that the car is pulling slightly to the left. so its moving the alignment of the axle possibly. this is seriously confusing lol

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