Friends,

Yesterday, as I drove around I noticed a "clunk" noise coming from the rear of my C6 everytime The car started to move from a stationary position. After searching the forum I found several posts that indicated that the clunk noise may have been assiciated with the differential fluid and the need to change it with a specific one, etc. So, I was thinking about taking the car to have the fluid replaced and check under the car while it was lifted.

While in my garage, I noticed the clutch fluid was black so I went ahead and drained it from the reservoir and replaiced it with DOT 4 a couple of times to clean the lines etc as much as possible. i did this 3 times. When I took the car for a ride, I noticed the clunk noise was gone and I wasn't able to reproduce it as I did the previous day. Cool!!!!

My question is... Is there a correlation between any "Clunking" in the rear of the car and the clutch or is this some sort of placibo effect???? I have very limited mechanical abilities so pardon my ignorance if there is an obvious answer.

Many thanks in advance.

Following. I get the clunk too, intermittently.

I believe the differential noise is usually most noticeable when turning, at least it was with mine. Clutch fluid could be the problem if it is interfering with movement in the clutch cylinder instead of allowing smooth operation. I’d check the axle nuts too, and if loose, replace them and torque new ones to spec.
Lastly, ensure sway bar ends are tight and not worn out.

Differential fluid and/or axle nuts...and both are easy to fix.
Many thanks!!