Audi V6 question

[mspivak@hyperdesk.com (Spivak, Marat)]

     This is a question for all Audi V6 owners out there.
     
     When my engine is cold, it makes a rubbing, grunting kind of a sound 
     when I start moving in first gear.  If I am in second, and slow down 
     to get RMPs below 1K, and then accelerate, the same sound comes out.
     
     I am suspecting the drive belt (not the timing belt), as sometimes it 
     makes this sound when it idles with A/C running, and I can see the 
     belt vibrate as I play with the throttle near the idle range.
     
     Has anyone has this symptom?
     
     Thanks,
     Marat
     
     '92 100