Vibration on a '86 5000 CSQ Avant

[Colin Hames <cchames@mm.com>]

Everyone,
	
	I have an light but noticeable vibration or hum between 55mph and
65mph. It virtually disappears above or below that speed.  It happens in
any gear, whether I am breaking or accerating.  I have had all the basic
alignment, balancing, tire & suspension stuff checked out.  The
vibration does not seem typicall wheel bearing symptoms either.  Are
there other common quattro ailments I am missing?  Maybe transmission,
differential or driveshaft issues.

Thanks,

Colin
cchames@mm.com
'86 5000CSQ Avant - 118,000K