My 2.4T SE Auto, 3 years old and only done 24,000 miles, has developed a low rumbling whine which alters with roadspeed and is most noticeable from about 18-35 mph. My dealer looked at the wheel bearings and said they were OK and put the problem down to slightly misaligned tracking on the rear. I have not had the tracking adjusted because I really don't believe this is the probelem and the rear tyres are wearing equally across the tread. It sounds mechanical - any ideas??