I have noticed a strange clunking noise coming from the rear of my car (00 z28 a4) when coasting. It is especially noticeable if someone is riding in the back seat. I haven't noticed anything indicating it is something mechanically wrong with the rear end. In other words, there is no jerking, no gear whine, no noises under accerelation only when coasting. It is more annoying than anything. If anyone has any ideas I would appreciate it.
p.s. I don't know if it is the rear or not but it seems to be coming from that general area. thanks.

 

I am going through the same problem right now. The clunk is sort of spontaneous. I dont know exactly what it is, but it will be going under thorough investigation either tomorrow or thursday. I'll let you know what happens.

 

I did some investigating today, and the only thing I saw that could possibly be causing the noise is the torque arm. There is also a similar noise when I put the car in drive or reverse. However, it is a little louder and has a slight clicking noise to it. If anyone knows if that is what a bad torque arm bushing sounds like could you please respond. Also there is a little play in the bushing in either direction.

 

I had the same noise. It got louder. Eventually got so loud I couldn't drive it. Brought it to the shop and they said I blew the rear. Sucks.

 

A broken transmission mount is common and causes an easily heard clunk.

 

Check out these links. Good diagnostic info.

http://www.ring-pinion.com/tech/techg0198.html
http://www.ring-pinion.com/tech/techg0298.html

 

I noticed this same problem in my 00 Z28 a4 just this morning going to work. I was coasting about 10-15 mph and I heard a clunk clunk clunk. I guess I will have to keep an eye on this thread to see if anyone comes up with an answer to this. The thing that stinks is I have only had the car for about 2 months and there is only 20 thousand miles on the car. An older couple had leased the car before me and I know they didn't rag on the car.

 

Is it a single clunk or repeated clunks? A single clunk while coasting can indicate a bad U-joint.

 

If it's a metallic sort of clunck, check the tightness of the two torque arm bolts. They may appear tight, but check them with a wrench anyways. This annoying problem went away after I tightened mine last year. This happened mostly during braking.

 

I got me a clunk too, can go for days without hearing it, then can hear it 2 maybe 3 or 4 times in a day. its always when i let off the gas and start to coast. its pretty much always at low speeds, like under 30mph or so. comes from the rear Im sure. checked u-joints by puttin car in neutral and tryin to shake the drive shaft, but its good. beats me, maybe something will turn up on this thread.

 

Mine ended up being a back-fire caused by an arching burnt spark plug. .....I was wondering why I had a miss. Forgot to check the obvious.

 

ttt