[E46/M3orBust]

So I've seen on a lot of online forums where people address this issue. They always assume it is the subframe but I had this exact same problem and my subframe was reinforced less than 10,000 miles ago with all new subframe bushings. It felt like my entire rear subframe was moving each time I accelerated or reversed. So I put it up on a lift and had someone accelerate and found the issue to be the Differential mounting bushings were very worn and the mounting hardware inside the bushings was moving hitting either the top or bottom of the mounting sleeve. If you have this issue get the car up on jacks and check those bushings under acceleration. I didn't have the tools to press these bushings out so I went ahead and just bought a new diff cover with brand new bushings already on. Hope this can help someone

[Jbonly21]

Originally Posted by E46/M3orBust

So I've seen on a lot of online forums where people address this issue. They always assume it is the subframe but I had this exact same problem and my subframe was reinforced less than 10,000 miles ago with all new subframe bushings. It felt like my entire rear subframe was moving each time I accelerated or reversed. So I put it up on a lift and had someone accelerate and found the issue to be the Differential mounting bushings were very worn and the mounting hardware inside the bushings was moving hitting either the top or bottom of the mounting sleeve. If you have this issue get the car up on jacks and check those bushings under acceleration. I didn't have the tools to press these bushings out so I went ahead and just bought a new diff cover with brand new bushings already on. Hope this can help someone

Thanks, I have that issue, do you have any pictures.

[JayR_e92]

I had the same issue when I first got my e46 M3 check out my thread.. it wasn't super loud but it was there.

Like you mentioned, other forum members first thought was subframe but I had a feeling it wasn't and that it was coming from somewhere along the driveline. Sure enough it was just a worn front diff mount bushing . Upgraded to a Revshift 80a front diff bushing and it completely went away!

[E46/M3orBust]

Originally Posted by Jbonly21

Thanks, I have that issue, do you have any pictures.

I do not have any pictures but if you are looking at the diff from the rear of the car there will be two rubber bushings (OEM) on the back and both of mine were bad. I'll include a photo of the rear of the diff and you can see both bushings on top.