I finished putting the rear end back together in my '62 C10. With the third member rebuild, new U-Joints, and switching from 3.90:1 to 3.38:1 gears, it drives like a completely different truck.

That pinion bearing must have been going out for a long time. The vibrations are gone, the whine is gone and the engine doesn't sound like it's screaming at speed any more.

Dave

1963 C10 Longbed Fleetside (1977-1987)
1962 C10 Shortbed Stepside (2003 - present)
2006 2500 Dodge Quadcab 4x4 (2007 - present)