Strangely my rear pinion angle is parallel with the tcase output and it still has the groan on throttle let-off. I have been running without my front driveshaft so I definitely know it's my rear driveline.
Also in 1st gear between 0 and 5 mph, the transmission has a strong low-frequency, high amplitude side to side vibration which disappears after I go above 5mph. No other vibes even at 65-70mph.
At Conclave, I looked at other people's rear diffs and pinions are not anywhere near parallel with the tcase output. Most of them were pointed up perhaps 5-8 degrees from horizontal. Is this what the stock rear pinion angle is like? I understand that there are actually two ways to run UJ shafts: with the pinion angles parallel, or the driveshaft-pinion angles the same for both pinions.
Any ideas, John? Could it be my pinion bearings?