E36 M3 Knock when shifting hard?

[Midnightfreak12]

Hey guys,

I have this problem where if i shift at 6500-7k RPM Quickly as if I'm Drag racing I get this rear end knock / clunk. It only happens from 1st -2nd or 2nd-3rd if I do it right. I've checked my diff bolt it's fine but the bushing is not. my subframe bushings also all look in good condition nothing looked torn although i didn't do much except pry on them. Central support bearing looked good as well no play along with the guibo which actually looked fantastic. I have a video below of the clunk that happens around the 40 second mark when i shift. Any insight would be helpful.

https://youtu.be/NkCE38HIS8o

[RRSperry]

I've checked my diff bolt it's fine but the bushing is not.
https://youtu.be/NkCE38HIS8o

Not to be an ass or anything, but I think you answered your own question.

[ben4bama]

The whole diff brace dropped down when you shifted. Not sure if it's supposed to do that or if the bushing that's shot you're referring to is on that brace or between the shaft and diff.

[LockDots]

Not to be an ass or anything, but I think you answered your own question.

+1 Shift clunks like yours are usually a bolt or the dif bushing. The bushing doesn't have to look torn or destroyed to be bad. The outside of the bushing may look fine, but the tears and cracks may be inside of it.

[Midnightfreak12]

Not to be an ass or anything, but I think you answered your own question.

Haha no worries, Just trying to get second opinions.

[Midnightfreak12]

This was solved by the way lol. Turned out to be roasted motor mounts that tore through the subframe and was just my motor lifting and slamming back down onto the subframe every time i did a hard pull heh...:( not sure why it sounded like the noise was coming from the rear but those bushings got replaced anyways as well as new front subframe / motor mounts. :P

[LockDots]

This was solved by the way lol. Turned out to be roasted motor mounts that tore through the subframe and was just my motor lifting and slamming back down onto the subframe every time i did a hard pull heh...:( not sure why it sounded like the noise was coming from the rear but those bushings got replaced anyways as well as new front subframe / motor mounts. :P

Wish you had told us before you replaced the subframe. We would have told you to get the subframe reinforcements welded in while you had the subframe out.

If your motor mounts go again, don't wait so long and weld in the reinforcements at the same time.