Originally Posted by mouseIX

I recently had a rear diff pinion bearing go out and it sounded like truck tires, very similar to your sound. You seem to have located the problem in the diff, next step would be to remove it and check turning torque of the pinion and then tear it down and look for damage. Problem is Mitsubishi doesn't sell rear diff pinion bearing preload shims. So I had to make some on a lathe from some shims I matched up off McMaster Carr. That is if you have a pinion bearing issue.