Hi all
Hope someone can help with this. I get a grinding,clunky noise coming from what sounds like the rear of the car when driving over 40mph, then if I let off the gas it kind of slowly clunks then goes away, then starts again. I thought maybe the rear rotors or a bad bearing but my mechanic checked these and they looked fine. Of course we took a drive to hear the noise and of course it didn't make any noises! Any suggestions?
2007 C280 4matic 60,000 miles

Have you checked out the bushings, those tend to wear out.

short clunk when letting of the gas pedal may be due to the drive shaft flex discs may be worn. More serious one to investigate is the grinding noise. That's not good. You need to identify the source of that grinding noise quickly. Differential can make that noise - highly unlikely for a 2007 C280 with 60K miles. Has the trans fluid been changed on this car? If not, this is a good time to do it. This will give you an opportunity to look inside the trans pan for any metal shavings.

Check side shaft CV joints, propshaft hanger bearing, flex discs & center U joint & splines.

Pray it's not the diff.

Also check all suspension bushings for damage on the rear.

Blown diff wouldn't surprise me. I had mine replaced around 80-90k, I believe.

Make sure you do not have a heat shield touching anything. This usually makes a scraping noise though. Look for shiney spots where things might be touching.

Thanks for the suggestions. I went back again to have these things checked and all looked good. They took another drive and heard the noises this time and determined it was the 4matic transfer case causing the shuddering/vibration(service bulletin TSB P-B 28.50/11?) I'll update again on Friday after I have this done.

Is the problem when you come to a stop and you are rolling foward easily while still on the brakes? I have this issue also. Along with the knocking from the fuel filler area. Or the back of the car, it's suppose to be a process the fuel system goes through to release vapors or something.

Yes - That could well be it. Let us know.

will this be covered under warranty?

^^^^ I would like to know about this too so I can take mine in and get this done........

I am at 60k miles too...........

I'm also interested in seeing what comes from this.