VW America has replaced my transmission three times. 10 July 09, 28 Oct 09 and 07 Dec 09. I am about to take it back again for the same problem and would LOVE to have some ideas about what is actually causing the problem. My last invoice reads "Auto transmission differential noise verified concern test drove vehicle found noise coming from auto transmission rear differential. call tech line. remove auto transmission rear differential oil pan and check oil contaminated with metal send photos to tech. remove and replace transmission. test drove re check noise okay at this time. I have gotten almost rude about asking what is causing it and can't get an answer. The transmissions get sent back to VW America and taken apart, but the dealership tells me they don't get told where the metal shavings are coming from.