Unfortunately, no. I went searching junkyards an local dealers for used rear diffs. I also searched for rear diff rebuild kits or parts. No luck thus far. My clutch has begun to slip, so I've been nursing the car everywhere. Once I get the time to replace my clutch, I'm going to do some more investigation. Lately, it's really hard to put my car down for a couple days or to even think of it at all. Some days I just think about trading it in for CooperS to relieve the thought of it!

One step at a time. Clutch will be ordered next week, hopefully installed shortly thereafter. I'll keep you posted.

 

I've had a similar problem with my car ever since I bought it 10 months ago. It's just the clunk, and it's only apparent when I release the clutch quickly. It's loud, very unpleasant, and it's a noise you can feel. I just changed out the clutch yesterday and found a split drive's side transmission mount and believed that to be the cause until I read this thread. I'll let you know if replacing the mount helps at all.

On another note, I noticed that the rear differential was saturated in a fluid/dirt mixture. I'm thinking this may be evidence of a broken seal. it's more saturated on the right side than the left.

Also my front CV joints need replacing. I'm guessing that's not the culpret here.

Do you think we could have the same problem?

 

please post updatd I am curious about this since Ihave same clunk when shifting form D to R and while cruzing on freeway at 50mph if I lift the gas pedal and than pres it again it does clunk, it is been like that ever since I got the car...

please let me know if you know something about this

 

I have had this issue in my 01 S4, broken sway bracket who'da thunk, huh! a friend same sound exactly, broken transmission mount, looked like it broke just from fatigue 120k miles...

It happens but, less likely its the wheel bearing or CV joint, if your CV boots are intact. Engine mounts start making noise when they begin to wear, so inspect transmission mounts/brackets. if they become metal to metal they get louder and louder. Rear diff comes to mind. I would check all mounts and go through everything starting with the cheapest and easiest to locate and inspect (All mounting brackets sways, suspension, tie rod ends etc) and go from there. As you go write it down then continue. Sometimes the sound travels through the car and as you already know its hard to diagnose and locate. Start small before you start tearing the car down it may be something simple.

night_rider check your snub mount and brackets as well.
Good luck Guys...
Tony

 

well I had the same problem on my ex a4 and Ihave changed motor mounts and it was the same problem, but I havent ever changed tranny mounts, how would you know if they are bad and is there a instruction you guys know how to replace them?

Thanks

 

Until I replaced my outboard rear cvs, they would clunk on loading - not so much unloading. They would also clunk when there was extremely quick transition in the rear suspension (pothole, tarmac divot).
They did not offer a hint of movement with vigorous shaking when suspension was loaded, but suspect they were partial cause for premature rear wheel bearing failure.

I've read that the rear hubs should be replaced when doing bearings as well, but can't understand the logic as they should not be a wear item (unless it's obvious of course).

 

I have the same clunk described. I took my car to a local transmission/ drivetrain shop and had someone drive it they said they didn't feel anything out of the ordinary. He said since it is AWD there will be some excess play in everything.

 

Ups... I have the same. Is there solution or what's the problem.

THNX

 

(just summing up the suggestions in this thread):

motor mounts (as well as brackets)
tranny mount (as well as brackets)
snub mount
sway bracket
wheel bearing
CV joint
rear axle
differential bearing
unsecured wheel/tire
wheel bearing

 

I bought a 2007 A6 Avant 3.0 TDI Allroad last month (130k miles, but in great condition) and have the same issue on mine. When I pull off from a standing start its like the rear axle is applying push a few moments after the front, so it feels like you are getting a kick in the rear. Like others have mentioned in here, you can pull off very gently and avoid this, but when it does happen, its not just an audible knock, but you feel the kick/push also. Would be interested to hear more from others with this issue and how/if they fixed it. Are we certain that this issue is not normal? I.e. it is definitely an issue which needs attention?