Drivetrain clunk. Somewhat mysterious

[04Moroblue]

So, I have a pretty consistent clunk I keep hearing and feeling from the rear diff area, particularly on/off throttle. I’ve even got it coming off the brake pedal in traffic as well.

Mounts all look good (carrier/front diff/trans). I even put 034 inserts in today to see if that may help.

I know the GIAC TCU tune doesn’t help as it is much rougher with engagement than factory tune. However, the only thing I can think is going on at this point is excessive lash in the driveline, internally in the differential.

Or that I’m just completely being tricked and the motor mounts are just super shot, as I will get a clunk here or there backing out and moving at odd angles.

Has anyone else experienced anything similar to this and had a good fix?

[plat]

It might be a symptom of a worn out diff or a diff that needs fresh lubricant. I used to own a rear wheel drive car and I get the same clunking sound when backing out or moving forward.

[04Moroblue]

Admittingly I haven’t double checked the fluid. However I’ve never experienced fluid cause that much of a noise. First thing on the list for tomorrow just to be sure. I’m sure it could use a change.

[theweebabyseamus]

Motor mounts could be possible, sure. What about a worn rear control arm bushing or a sway bar end link?

[04Moroblue]

I’ll inspect a little closer when I get underneath it tomorrow. Being under the car the rear control arm bushings/sway bar all looked like solid rubber. And it doesn’t exhibit any issues over bumps or in turns. Just solid clunk when going off/on gas at lower speeds.

[u2nelson]

So, I have a pretty consistent clunk I keep hearing and feeling from the rear diff area, particularly on/off throttle. I’ve even got it coming off the brake pedal in traffic as well.

Mounts all look good (carrier/front diff/trans). I even put 034 inserts in today to see if that may help.

I know the GIAC TCU tune doesn’t help as it is much rougher with engagement than factory tune. However, the only thing I can think is going on at this point is excessive lash in the driveline, internally in the differential.

Or that I’m just completely being tricked and the motor mounts are just super shot, as I will get a clunk here or there backing out and moving at odd angles.

Has anyone else experienced anything similar to this and had a good fix?

I recently changed out my front drive axles at just 55,000 miles. Since brand new, I had a persistent drive line clunk that is now gone, it was the CV axles for sure. Audi techs told me it was normal for Quattro cars, I now know its not normal as the new axles are a huge improvement. I also poured the grease out of the old OEM axles like motor oil, the Audi OEM grease was done. BTW, I could not tell where the clunk was coming from before, only that it was drive line.

[04Moroblue]

I recently changed out my front drive axles at just 55,000 miles. Since brand new, I had a persistent drive line clunk that is now gone, it was the CV axles for sure. Audi techs told me it was normal for Quattro cars, I now know its not normal as the new axles are a huge improvement. I also poured the grease out of the old OEM axles like motor oil, the Audi OEM grease was done. BTW, I could not tell where the clunk was coming from before, only that it was drive line.

Something to think about. Mine is DEFINATELY rear. However driving around in comfort mode seems to really diminish the frequency. Started thinking maybe DSG adaptation issue. I tried to perform the adaptation (I’ve done it before) but no matter how I do it keeps aborting for safety.

Following all the prerequisites. So I’m kinda stumped now!

[AudiS4SD]

Any update OP?

I also have the 034 mounts and have since developed a clunk when rolling away from a stop and releasing off the brake when in traffic. I suspect it is simply NVH from the mounts, but I'm not sure. Hopefully, no long-term damage is being executed...