*****HELP*****Vibration in Quattro*****HELP*****

[Dupree_Robert <DupreeR@tpd.eds.com>]

*****HELP*****
I have an '87 5000 CS Quattro and it "hums" maybe even "grinds" when cold 
and hot (although not as loud) between 35-55 miles an hour. The sound is 
very similar to driving allong a constant "rumble strip" on the highway 
although normally about half that volume and lower in pitch by about 2 
octaves.  It sounds like it is located on the left hand side of the car, and 
is there whether the clutch is engaged or not.   Had the CV joints visually 
inspected and the wheel bearings don't feel bad...(Thanks Graydon for all 
the advice)   Thought it was a ratteling Catalytic Converter, new one is on 
now with no change in noise.  Thought it was the tires...  New set (Dunlop 
60 A2 (215 60 15)) and no change.  Aaarrggghhh!  The Audi Gods are 
tormenting me.  Today I am going to take it down to the local shop and put 
it on a hoist and get the drive line moving at about 45 miles and hour, but 
I fear that because the suspension is UNLOADED at this point it will not 
make any noise.

ANY IDEAS?

All help appreciated in advance...  and I am running out of money...  :(

Robert Dupree
dupreer@tpd.eds.com

PS: Should I have the CV joinst repacked just in case?