Center Driveshaft bad?
 

I have a 2003 Allroad 2.7T with 80,000 miles on it. Under very hard acceleration (pedal all the way down) I can hear a grinding/vibrating noise coming from right underneat the shifter. The dealership "guessed" it was the bearing in the center driveshaft going bad. Noise only happens when its floored...anyone heard of this?