...different matter. If you changed the front seal, it's really easy to end up with whine as it's very particular how tight the nut is torqued. The crush sleeve is really meant to be crushed one time only and should be replaced to do it right. If it's not changed, you should only tighten the pinion nut to a couple pounds or it will crush the sleeve further changing the pinion to crown gear alignment, most likley giving you the whine. Rear ends are tricky business at best to set up to be quiet.
Though no one can go back and make a brand new start, anyone can start from now and make a brand new ending. - Anonymous