I have a 20T Quattro, which exhibits a very strange noise. This noise only occurs if a reverse and brake after I have driven a reasonable distance at relatively fast speed. I must have travelled for at least 15 miles at 60 mph or faster. Audi have informed me that all A4 Quattroâs make this noise. I think it is strange as I can feel movement in the steering wheel. The car has been in the shop 6 times over a 3 month period and numerous parts have been replaced. Any Ideas?