Rear End Noise
 

I have a new 2003 C230K delivered on 10/02/2002 with 6 spd and c7. I have a whine coming from the rear end only when decelerating from 50 to 40 mph. The whine is present whether the clutch is engaged or disengaged and no matter what gear the transmission is in. There is no whine at other speeds or when accelerating 40 to 50. The car now has about 2200 miles and the sound has not changed - no worse, no better. The service manager at the MB dealer drove the car and says it is the tires on the c7 package(continentals). I find this hard to believe and think it is coming from the differential. What are your thoughts and what should I do about it. Thanks