After installing a used 4.56 ARB 8.4 third, and doing rear axle maintenance, I have a vibration that is not present except right at 27 and above 50MPH and ONLY on deceleration. Putting the truck under load completely takes care of the problem. Its a vibration and a noise like going over rumble strips. Its especially noisy because I am running a solid carrier bearing. I am not sure where to start, driveshaft vs. third.
The pinion angle is probably in the negatives (as in practically pointed down). There was a super small degree shim that I pulled out, but can that small of a difference in pinion angle make noise? Does it sound like any type of driveshaft or even transmission tailshaft issue? Its not wheel bearings, tires, balance. Its somewhere between transmission and rear axle
I'm starting to think it could be runout in the ring gear? Would a shop charge less to double check the third or should I just live with it and regear down the line?
Thanks in advance!