My new A3 SB TDI Quattro arrived Wednesday. Its back in the garage already. Driving home last night I noticed an faint intermittent high pitched metallic scrape / whine from the back of the car. Then over the speed bumps approaching home there was a clanky metallic sound followed by some loud metal-on-metal screeching. Speed dependent but not related to brake use. Intermittent. Looked under the back of the car, but nothing seemed to be adrift to my untutored eye. Any offers - wheel bearing? Something scraping on drive shaft? Haldex?? Dealer can't look at it 'til Monday, so its Shanks' Pony for first week of SB ownership.