While you're under there, really jostle the driveshaft around, looking for any play. Center support bearing and support bearing mount likely deserve replacement if miles are high.

In my case, the bearing mount was completely worn away; the driveshaft could be deflected up and down a coupla centimeters or more. Bad! Still, the car was running pretty quietly. Interestingly, the bearing itself showed no evidence of slop. Replaced on principle. Both flex disks and shaft coupling boot, too.

Next (when?) I gotta replace the transmission output seal and re-seat/torque down the output shaft yoke. Play in the output shaft was, I'm sure, responsible for much of the wear in the driveshaft components.

Still not clear if there's a bearing on the trans output shaft to be replaced.

__________________
'83 300 SD
'05 E320 4Matic
'06 BMW 530 xi
'68 Triumph TR 250 - The only car I ever loved more than the Mercedes; who needs electricity, anyway? - Damn, why did I sell it?!
'59 Jaguar 3.4 'Le Chat Noir' - Damn, why did I sell it?!

It's difficult to make predictions, especially about the future.
- Niels Bohr