I have a 2000 A6 4.2 and am experiencing a noticeable repetitive thumping from the front drivers side wheel area when I have the steering wheel turned all the way left and moving. It is most noticeable when I'm reversing.

I just replaced most of the control arms and did both axles when I was under there . . . any ideas on what it could be? My friend did most of the work, perhaps we didn't line something up right?

Any thoughts or help much appreciated. Love the car and like keeping it in good shape . . . and would hate to be slowly destroying the parts we just put in

 

I would check to make sure there are no interference between the parts you replaced.. I would concentrate most on the axle/halfshaft as the thumping your describing is rotational.. I have seen the clamps on the CV boots hit suspension comonents, heatshields and cause thumping noises as the axle rotates and contacts parts.