[Roadie]

Well, you can replace the front pinion bearing by removing the nut and removing the seal and bearing. To replace it, you need a new crush sleeve, bearing, seal, and nut. Then you need to torque the nut enough to crush the sleeve (about 400 ft. lbs. in my experience). Crushing the sleeve to get the bearing preload just right is tricky. If the diff is totally disassembled, the preload is supposed to be enough to take about 25 in. lbs. of torque to turn the pinion with nothing in the rest of the diff. In order to get rid of the whine, you may have to replace the ring and pinion gears bearings etc, the whole tomale.