I've got somethign screwwy going on in my driveline. I replaced the rear axle with a newer one out of a 96 with only 80k on it thinking the chipped up ring gear was causing my problem but it was not. The vibration is coming from somewhere else and as best as I can figure it's the T-Case or driveshaft. It usually only does it under acceleration very loud them stops after I let off the pedal. All the U-Joints are new and the transfer case and rear are both full. So I'm figuring a messed up driveshaft or something goofy in the transfer case. I'm kind of leaning away from a driveshaft issue due to the fact that it quits when I let off the pedal. I figure wether I'm on the pedal or not the shaft is still spinning so it should still vibrate.