Mark the front and rear halves of the driveshaft before you pull the front off to change the bearing and carrier. You MUST get it back EXACTLY as it was before, or you risk serious vibration. It is not, alas, keyed like the Volvo, where it will only go in one way!
You don't need any grease for the carrier or center bearing, the drive shaft is non-servicable except for replacing the bearing and carrier.
The clunk and hard shifting are most likely a vacuum leak resulting in low vac to the transmission modulator. Look up the numerous postings on this subject. The driveshaft if fine unless you get a "bad muffler" noise that is not a bad muffler, accompanied by floorpan vibration centered just at the rear of the front seats. If you can feel the floor vibrating when you put your hand on the drive tunnel at speed, you have a bad carrier bearing mount or other driveshaft problems.
If the car just bangs hard when it shifts, sounds like the rear end is thumping around, you have a vac problem, not a driveshaft problem, leave the driveshaft alone!
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!