I'm experiencing a rumble, crunchy, kind of a flat tire, loose wheel noise and feel upon acceleration, in the rt. rear wheel area usually in 2nd gear(manual trans). '99 A4 Avant, 158k, all new brakes and calipers. I've checked visually. It only occurs on acceleration, seems like going over mild speed bumps. Any thoughts?

 

wheel bearing maybe? does it get louder when ur turning to the left or right?

 

Sounds silly I know but check your tread for gravel stuck in there. I had this happen in my truck and thought I blew a tire. Sounded crunchy and made a THWOP THWOP THWOP.

 

Is your car a quattro? You may have an issue with the rear diff or a CV joint in one of your rear drive axles. Take a look at the boots on the joints for cracks, rips, or punctures.

 

the car is a 1.8t quattro. No additional noise on turns. just for a few seconds on acceleration