I have reassembled the driveline after,
- shaking the hell out of it looking for places where things may bump
- replacing the diff mount,
- replacing centre support bearing
- replacing driveshaft bushing
-and looking for any clearance issues or loose bits.
And I have the same sound. I truly thought it was the centre support bearing because it did have some movement in the bearing itself though it was new.
My next move is to have a friend who is a very good shade tree mechanic listen and diagnose. The next move after that is off to a shop in town that specializes in old European cars. Bert helped me with my Land Rover resto.
As it is a sound from a rotating something, an interim step may be to give things a very very thin coat of grease, go for a drive, and then inspect for signs of touching. I have very closely inspected every element of the underside and have not seen any signs of rubbing (i.e, polishing, rubber dust, rubbing, missing paint).
Again, any insights and advise are welcome
Honestly this has driven me nutz (no pun). My plan was to drive the bavaria lots including a few road trips. I have not been able to drive it at all except around the neighbourhood looking for the cause of this sound. Oh well...an acquaintance once told me when I was beaming after 'finishing' a 2002 resto. He said, 'thats kinda boring; what ya going to do now?; I like to think there's a transient 2% of old cars that need work; this way theres something to fiddle with'. Well...maybe thats why we do what we do...thats why we love these old cars...fun to wok on, fun to drive, look great, a nice way to spend some time. Nonetheless frustrating when I had expectations of nice cruises to the cabin, mtns, prairies. I'll get it figured. Thx for letting me rank a bit, Forum!
All the best,