'87 4000 Quattro CLUNK!

[Christopher Flanner]

I have read all of the past listings on this subject but they haven't 
led me to a solution of my problem.  Please advise.

I recently bought a second 4k Quattro through an auction.  I was hoping 
that it wouldn't make the clunk sound that my other 4kq makes when 
reversing driveline rotation (reverse to forward gear) and during some 
forward shifts.  However, it does.  I can get it to clunk by letting 
out the clutch while at a standstill.  I've checked the transmission 
and rear differential bushings and they are all good.  The subframe 
bushings look good too.  There is a lot of play when I rotate the 
driveshaft by hand, though.  I thought (and think) that there is a 
problem with gear "slop" in the differential(s).  A respected shop that 
I talked to said that probably isn't the case and that if the 
differentials weren't making whining noises, they were fine.  I 
inquired about getting a rebuilt differential and they thought that was 
the wrong direction to take.  They haven't actually inspected my car, I 
should note.  

I bought this car to receive an MC turbo engine but I don't want to 
start the conversion until I have a non-clunking drivetrain.

Any advice will be appreciated.

Chris
Milwaukee, WI