I have a 2004 Rubicon w/ 6" fabtech front end, Clayton Offroad 3-link setup in the rear, 2" body. Ive had this setup for years. I now have a wicked ROAR anytime im moving (acceleration, decelerate, turn left or right) It does however get worse when i let off the gas. It is a " whomp whomp whomp" and of course it gets faster the faster i go. I cant tell where its coming from, but ill tell you what ive done. Pulled the front driveshaft (no change) changed the front hubs ( they were trashed) i just pulled the rear shaft and drove it in front wheel drive and the sound was CONSIDERABLY quieter but you could still hear/feel it. So i pulled the rear end apart. The driver side rotor was cracked at the base of the of the brake surface. Both rotors seemed warped (visibly) but after i took them off and spun just the axle shaft (still in the tube) it seemd warped as well. On ONLY the passenger axle shaft spline there was just a little bit of "silver oil" none on the driver side. The entire rear end was warrenty swapped by the dealer about 10, 000 miles ago (EVERYTHING NEW ie gears, axle shafts, locker) but now that the axle is apart, when i spin the input yoke it spins about 3 times fine and then you can hear a sort of rumble. I couldnt get the ****** diff cover off due to the glue. You knwo after i typed all this i think that ive answered my own post... my Ring gear is probably shot huh? But if you have any other suggestions.... PLEASE let me know!!! also seems like a driveline vib, but its not constant above 75, it comes and goes as in RRRRRRRRRrrrrr................RRRRRRRRrrrrrrrrrrrr . I know that you just read that and laughed....you cant spell sounds!!!!