Hi I've got a funny buzzing noise, possibly coming from the rear of my car ? It is usally there between 45 & 55mph in most gears. Does anybody know what could be causing it? I did take a look under the car at the weekend but could not find much, all the exhaust brakets & rubbers are all ok. There is a lot of heat sheild & plastic aero shielding under the car, could it be that? I have also read about the prop shaft bearings seizing up, but that looked all ok, but is there way of checking? It is a 56' 2.0TDi Quattro. Cheers.