Yes what your describing is exactly what I have. Its like a rumble as soon as you let off the gas, they thought it was my tires but I verified that it isnt that or my driveshaft for that matter. The only thing is that mine happens anywhere from 30-40mph, if i let off the gas at a lower speed it doesnt happen for some reason. WHat speeds does yours happen at?
The preload has to be checked by a gear specialist who knows what they're doing, they gotta inspect the bearings to make sure they aren't going bad, and to do that they gotta open up the rear diff.
2004 Silver Jeep Rubicon
6" Nth Degree Longarm Kit