I think I had a pinion bearing go bad. Constant whine/growl. Horrible a 80mph. Just annoying at 45mph. No different sounds as in a coast or drive side gear whine. Pulled it out tonight. I will be pulling it apart tomorrow. Need to make a cradle to bolt to my bench, and a case spreader yet. All new bearings and seals going in, perhaps a differential clutch pack rework while it's out.