Last week I took a left hand turn pretty hard on my crappy stock wheels/tires and the back end stepped out a bit. I heard a pop/clunk sound from the rearend and backed off it.

Since then I've gotten a vibration in 1st and 2nd gear at low rpms (2000-4500) under moderate load, like accelerating from a traffic light. I can hear and feel the vibration, and it definitely seems to be coming from the back end of the car. It doesn't happen at WOT and doesn't happen in higher gears. It's particularly bad accelerating through left turns (nothing crazy or spinning tires, just regular driving).

I've checked over the coilovers and diff, everything appears to be tightly bolted down, as is the driveshaft. I don't get any vibration or whine at cruise or acceleration in higher gears. Transmission shifts fine. I've swapped wheels and it still does the same thing. It doesn't feel like I have any slop in the wheels/wheel bearings.

Any thoughts on what it might be? Anything I should check or try to eliminate as an issue? I'd appreciate any help or suggestions you may have.

 

I think I've found the culprit to my vibration. I cracked my PPF! There's a crack across it where it bolts to the diff. I'm guessing I just need to replace it at this point or would there be any hope for welding it?

 

Cracked PPF? Holy crap. Pics?

 

 

the thread title is the greatest inuendo ever

 

Weld it!

 

This thread title turbed me on.

No don't weld it damn it. Buy a used one it is like $3.

Also, I cracked my PPF too. Right in the middle bisch

 

I felt pretty special when I found the crack, but I've read several other instances of it happening so I guess it's nothing impressive. I talked to a welder friend and he said he'd want to have it pulled out in order to weld it, if it's got to come out anyway, I'm definitely putting a new (to me) one in.

 

was it a very loud and audible vibration??

 

It's only noticible when accelerating in 1st and 2nd gear at low rpms. I can hear it and definitely feel it, but the 2 passengers I've had in the car didn't even notice.

 

Dopple managed to crack his too iirc.

Glad you found the issue.

 

not my issue then :( nice one finding the problem.. funny how a small crack can cause vibrations