Clink sound when I change direction of the pressure on the differnetial

[Gemcoska]

Hey guys,

This sound has been happening my 2008 E92 m3 for a month now and I don't know what it is. Seems to happen when I'm bouncing on/off engine braking or applying initial acceleration in 1st. When I'm in stop and go on the 405 it happens all the time. Some searches indicate that there might be a loose bolt in my diff. Where would these bolts be? Others say it might be a bad cv joint. Others say it's an indicator of a diff going bad. I replicated the sound going
back and forth in drive then I think I was able to replicate a quiet version by turning the wheel hubs while the car was on stands. Hoping someone here will have some obvious answers.

The sound while driven

The sound on Jack stands


Thanks in advance

Rob

[Gemcoska]

Found this: https://www.m3post.com/forums/showth...t=differential

But it seems like the solution to replace the driveshaft maybe a matter of preference vs safety.

[chocstraw]

Dropping into this thread because I have a similar sound after having a CV disconnect after improper torquing after doing solid subframe + poly diff mounts.

I live just north of LAX and I'd be down to have a diagnosing session with you. I repacked the joint, checked torque, marked everything with paint pens (no rotation so far), and a few other things. DM me your number if you'd like.

next step is to chock up the front wheels, raise the whole rear, and spin the wheels and see if I can isolate the sound that way.

meanwhile I've been debating which CV to go with if it's that. Junkyard pull (rarely fails unless drag racing or drifting) or this one. Someone on reddit has been running one with a welded diff without issues. Still feels stupid to cheap out on an annoying job to risk it failing eventually.

[nurburgracer]

Originally Posted by Gemcoska

Hey guys,

This sound has been happening my 2008 E92 m3 for a month now and I don't know what it is. Seems to happen when I'm bouncing on/off engine braking or applying initial acceleration in 1st. When I'm in stop and go on the 405 it happens all the time. Some searches indicate that there might be a loose bolt in my diff. Where would these bolts be? Others say it might be a bad cv joint. Others say it's an indicator of a diff going bad. I replicated the sound going
back and forth in drive then I think I was able to replicate a quiet version by turning the wheel hubs while the car was on stands. Hoping someone here will have some obvious answers.

The sound while driven


The sound on Jack stands


Thanks in advance

Rob

Sounds to me to be the classic “cowbell”. Centre support bearing may be the culprit.

[Bmwdoubles_]

That’s sounds like the infamous cowbell to me. If you drop the DS might as well change out the flex disc and the CSB. The fix for the cowbell is when you pull apart the DS put gear grease on the splines. Cowbell solved.