I have a 98' Audi A4 automatic awd and quattro engine with 1.8L turbo. whenever I begin to accelerate, my car rumbles and it feels like an axel issue but I have no clue. If you have any idea let me know, it seems to go away after I'm driving 35-40 mph so it might be a transmission thing with the first and second gear but I dont know. Please HELP!

 

could be a ton of things...transmission mount...engine mount...axle, suspension, drive train...any more info would help a bit....could be as simple as bad tires, unbalanced tires, bad alignment etc.....you need to narrow it down a bit more.....specific RPMs it does it at? If you're in Neutral and rev the engine, does it shake then? does it make funny noises as well besides the shaking? does it make noises turning corners? etc....

 

sounds like its a rotating piece? ironically the speed noted is famous wheel bearing territory. since you have the automatic, as do i, 35-40 is like 4th gear there sparky, unless you are romping on it to produce these results? more info like marc was sayin