BMW E46 knocking noise from the rear

[JadielM]

A random, but horrifically evident, "knocking/thumping" sound has begun to originate from the rear of my E46... This happens whenever the clutch is let out in any manner that isn't painfully slow and gentle. I know for sure it isn't the diff guibo's/flex couplings as these were replaced with OEM items under 30k km ago . It doesn't feel like the propshaft either, as there's no rotational sound/vibration, the noise is localized to when the clutch is released between gear changes.

A bit of googling points to the diff bushings, but I'm not completely convinved. Anybody have an idea of what else it could be?

 

[Nikhil]

Rear diff bush is the most likely culprit. Theres 3 bushes normally the biggest one wears but i would suggest looking at replacing all 3. The other potential issues might be rear shock mounts, rear trailing arm bushes or the least likely being subframe.

 

[applehero]

I have the same issue. Guibo and centre bearing were replaced by previous owner. My Diff Mounts were cracked. Replaced with Polybushes. Noise still there. I suspect it could be play in the diff. Motor and gearbox mounts probably also need replacing.

 

[Dewald Basson]

I had thumbing clucking noise coming from the rear. Replaced the guibo and diff bush, greased the cv's. Sound was gone.

---

I had a thumbing clucking noise coming from the rear. Replaced the guibo and diff bush, greased the cv's. Sound was gone.

 

[Pho3niX90]

If you have checked the bushes and convinced that everything is fine, check your disa valve as well. I had a horrible noise that was linked to the clutch when my disa went on the 330. Originally thought it was the clutch but once the disa was replaced it wad all gone. Think it might have been due to the car misfiring and causing vibrations.

Sent from my SM-N9005 using Tapatalk