Saw your thread on the gasoline side. If I understand the issue, you've pulled the shaft halves, replaced flex disc(s), identified the match marks and re-assembled the shaft halves with the marks aligned and installed same with a new carrier bearing. Now you have a vibration.

Try putting the car up in the air (lifts are nice but jack stands could work) with the wheels hanging, and spin the tires slowly (by hand - engine off). Look at the tires (lumps, wobbles?), then the half shafts from the diff, then check the D/S. Its quite possible you'll spot the issue (mis-alignment, shaft wobble, binding bearing, mis-aligned flex disc, binding shaft slip joint, etc). Good luck.