E92 DCT thudding noise from rear end

[///MFreak]

Hey all!

I'm having a weird kick and thudding noise from the rear end when applying any kind of power even 15%. I have changed the diff fluid and bushings and center support bearing but still no luck.

Went to a mechanic and he said there's a play in one of the cv joints and maybe the diff needs rebuilding, I've installed a used diff and the play disappeared. The kick/thudding noise have lessened but still noticeable.

I'm getting frustrated because of this issue and I hope someone has resolved this issue and can help me with it.


Below are a couple of videos that shows you the kick/thudding noise appearing when applying power.


https://youtube.com/shorts/hlO_gJH6-v4?feature=share

[amrazM]

ive heard that thudding alot in bmws. its usually from the diff, since you installed a used diff thats probably what the issue is.

[///MFreak]

Originally Posted by amrazM

ive heard that thudding alot in bmws. its usually from the diff, since you installed a used diff thats probably what the issue is.

Originally Posted by amrazM

ive heard that thudding alot in bmws. its usually from the diff, since you installed a used diff thats probably what the issue is.

I've installed the used one to test if the noise will disappear but it didn't, it lessened. So I've installed back my old one.

[tdott]

This might be the best way to fix it.

https://racingdiffs.com/products/bmw...42498059075820

[///MFreak]

Originally Posted by tdott

This might be the best way to fix it.

https://racingdiffs.com/products/bmw...42498059075820

Thanks! It is actually the left side that has play.

However, is it actually the problem?

[nycplumber]

I had this on my last car and it was more pronounced when I installed solid subframe bushings. I believe its the diff

[DrFerry]

The clunk sound in the video is primarily the sound of the backlash between the ring and pinion gears being taken up when on and off throttle. The backlash increases with wear but is initially set when the Diff is assembled with a dial gage. If it's set incorrectly then overtime the gears wear and by around 50K miles many BMW's have worn diffs with the clunk. Search the forums using the Advanced Search page with keywords "Diff Clunk" for the thread title. Additionally, the OEM E9X M3 Diff uses the Visco-Lok Limited Slip mechanism which is also prone to wear. As tdott mentioned and linked, kits exist to repair the Visco-Lok clucthes.

The backlash between the ring and pinion can be adjusted by a competent shop. The key is knowing what value the set it too. driftflo is your man for all things BMW Diff related but he's in Germany. See his thread for more information:
.
https://www.m3post.com/forums/showthread.php?t=788992
.
More on OEM Visco-Lok:
.

.
https://www.m3post.com/forums/showthread.php?t=1404054
.
https://www.n54tech.com/forums/showthread.php?t=36093
.
https://www.m3racing.de/sperre.html
.
Example of ring gear teeth
.