As long as you're unbolting the driveshaft, check the center bearings (or any bearings for that matter). I just recently replaced my entire driveshaft due to a seized center bearing.
It was causing similar issues to those you describe. You SHOULD be able to just replace the bearing; mine was just especially f'd.
| 2004 BMW 325xi ZPP/ZCW
220,000 miles and counting...