Hey all, I've had my '01 A4 2.8 Quattro Automatic/Tiptronic since May, and just had it for my first service (60k mi) at the dealership. The main reason I sent it to the shop was I have started noticing a popping/thumping sound when going from coasting to acceleration. Doesn't have to be hard acceleration, but just going from coasting (where the wheels are pulling the engine) to accelereation (where the engine is pulling the wheels), creates the thump. I can also feel that something goes "thump" somewhere, but can't really say where it comes from. Also hear/feel the thump when just coming to stop (while the car is downshifting to 1st). Just paid the dealership and arm and a leg for changing the propshaft seal and the right hand front transmission axle seal (apparently it was leaking transmission fluid from both places), but it didn't make the thump go away. The mechanic claims he did not reproduce the "thump" during a test-drive, which first really annoyed me, however after picking the car up this evening I noticed that the phenomenon doesn't really show up until after the car has been running for a little while (5-10 mins). It's like there is a slack somewhere in the drivetrain that shows up more after the car is warm (or maybe it's just that the auto-choke goes off after a while, lowering the idle/coasting rpm of the engine).

Any thoughts/tips that I can relay to the mechanic when I take it back?

Thanks a lot,
einar

 

I have the same issue with my 1998 A4 2.8 Q. Any ideas please.

 

I have exactly the same problem with my 99 A4/V6-auto.
Has any one found out what causes the problem ?
Thanks a lot!
-Tat