Vibrates like crazy in 4WD, fine in 2WD

[woody80z28]

U-joint! Duh...why didnt I think of that. I'll bet that's it.

Swapped in the BW tcase when I swapped in the NV4500 out of a 1-ton. Trans, tcase & rear dshaft are all 1-ton, rear is 6-lug 3/4-ton and the front end is still 1/2-ton. But it's been like that since 2011.

 

[woody80z28]

Yup, u-joint. Piece of cake. Got both the front joints on the way from Rockauto for like $25 shipped. ACDelco "professional grade".