Buzzing sound from rear of car!

[E36M3Ranger]

Hey Everyone, I drive a 1998 M3/4a in the last couple weeks I have noticed a humming or buzzing sound comming from the rear of the car, it is particularly noticable on the inside with the windows up. It only happens when the car is in drive or reverse, and as soon as I give it a little gas the engine speeds up and it goes away instantly until I come to a stop again. Just wondering if anyone has any idea...it sounds like something toward the back of the car is loose and that it might have to do with the drivetrain...Thanks

[jason11]

Shock tower mounts maybe ?

[Estoril ART]

No, probably not. The shock tower mounts wouldn't make a buzzing or humming sound.

[BiMaW]

might want to check your rear wheel bearings or CV joints.