So I’ve been driving this thing since the lift. It has a low speed driveshaft vibration.
Two options
One would be to shim it 3% pointing the pinion down to get it back at 0* and 0* and stick with the standard joints.
Two is to rotate the rear pinion up 10* and run a double cardan shaft.
After talking to Tom Woods at length about it, he sold me on option 2.
It’s interesting that the rear 4 shafts I have built for all of my builds are 21” long with standard Ujoints and Ive never had a vibration issue.
Mind you the shake is on acceleration and only at low speed which is described well in this tech from Tom Woods
This shaft is 23” long with a 18* angle.
View attachment 3622981
Article … see angle related. Joints are good. Did not do this prior to lift