[onewhippedpuppy]

Only while in motion, still there with the clutch in. That's one of the first things I checked, so I know it's from the transmission back.

Joe, I just did the center bearing Sat/Sun, everything else looked fine. U-joints felt tight, I marked the driveshaft prior to disassembly to keep proper alignment, everything felt ok. At that time I could not see any OBVIOUS damage to the CVs, because I looked. I know they can be bad/dry and show no obvious outward signs. The weird thing is, normally CVs are worse when you turn towards the bad one. This is the same, straight or turning.

Steve, it doesn't feel like an unbalanced tire, but I suppose I could try rotating them to see if it changes.