I'm from Bosnia (Europe), I got 2000 Jeep WJ 4.0 few months ago, and now I have some problems, but here isnt any good mechanics for Jeep, because there isnt too much jeep vehicles.
My problem happens only in first gear when starting hard from a dead-stop, and also when moving 20-30 mph and then press gas pedal hardly. Then Jeep is jumping and vibrating 2-3 seconds or until I let off gas... I posted video of my rear driveshaft, is everything ok here:
zSHARE - Video-0007.mp4
P.S. Sorry for my bad english : )