With no change in noise while accelerating, de accelerating, or pushing the clutch in, and being solely speed dependent. It shouldn’t be the gears themselves unless they had a new guy and he set the backlash at an absolute zero. Does it sound kinda like those little electric kid jeeps driving around, or more like a front wheel bearing roar?Hello, I am a new member but have been visiting this site for months learning about my TJ. This is an awesome forum. I have a 2004 X model with 4.0 and 5 speed manual. I plan to move up to 33" tires so I had it re-geared from 3.07 to 4.56 by a local offroad shop. The shop did 2 heat cycles on the gears prior to me picking up the vehicle to ensure the break-in process was done correctly. As I drove away I noticed a hum beginning at about 45mph that got progressively worse the faster I would go (seamed to come from rear diff). I kept the jeep below 55mph hoping things would smooth out. After about 20 miles I ran it up to 60mph and the sound was significantly louder and I could feel it through my seat and it was resonating inside the jeep. The noise would increase with speed but not really impacted by acceleration or pushing in the clutch. I pulled over and the rear diff was very hot to the touch. I sat for about 20 minutes to let it cool a then limped back to the shop using back roads keeping my speed below 45. Upon arrival they used an infrared thermometer and the rear diff was 185 degrees. They didnt seem too concerned but said they would look into it. The shop did mention they had an issue pressing on the pinion bearing. Apparently they had to order a second bearing as they were never able get the first one to fit. The shop is a Yukon certified installer and used Yukon gears. I am concerned because the cost of the regear was not cheap. Any insight or wisdom I can possibly share with the shop is greatly appreciated. Thank you.