I have a 2000 S4 with about 114K miles. On initial acceleration only, I hear just one thunk from my front end and then all seems fine. Its as if one of the tires...or both are pushed back. This only happens if I attempt to get a pretty good jump from a standing start. If I'm casual about the acceleration, I don't hear the clunk at all. I think the same goes for reverse. Any ideas?

 

could be engine mounts.. could be upper control arms.. more than likely both are bad...

 

Could it have to do driveshafts? just a thought

 

my guess would be either the control arms or engine mounts as well, crawl under and see if you see any evidence of fluid leaking from your engine mounts, sure sign of problem. also upgrade your front snub mount to a poly urethane one, does wonders and that might actually help your problem

 

yeah, funny cause i just removed my front clip last night to do a turbo swap and i checked my mounts.. noticed that my driverside mount had actual broken looking metal pieces loose, so loose that without removing the mount i could take a screwdriver and get the pieces to fall out.. and that snub mount can look like its in good shape but if its oem itll flatten out and stuff and be sitting in its cage all loose and such... as was mine...