I took another look today and did notice something I was wondering about, the shaft is two peices and at the split, it goes through a bearing loop that is bolted to the frame. I can wiggle the shaft pretty substantially inside that loop. Potentially my problem?
I think that could be your issue. I'll look into it some more. Sadly I don't have a two piece drive shaft so I know that isn't my problem.
06 2500HD CCSB: EFI Live by duramaxtuner, Blocker plate, Airdog II 165, Banks 4" Exhaust, Banks Intake, 6" RCD lift