Just put a new moser 12 bolt in my car. I put a Yukon differential and gear set in it. Had to return the differential due to it not slipping when turning. Tried their recommendation on freeing it up but didn’t work. Put about 50 miles on them then. The gears had a whine in them from 40 to about 55. After putting in new differential it started about the same range. After about 12 miles it had expanded to 20-60 on and off the gas. Shop said the gears had a good pattern...Right in the center. Going to call Yukon about it but they will probably say that’s just the way it is but I think this is very excessive. I can seen a 5 mph range of some noise but not 40!