how the heck does one strip the splines on the gear? Thats what really has me puzzled.

I was traveling in a straight line, on the higway, at 65mph. I had just made the drive to a town 20 miles from home, done my shopping and was returning.

The center section was a used chunk, but never had any vibrations, and visual inspection before installation to be sure the thrust buttons were removed, showed nothing odd. As assembled the differential had less than 200 miles on it, 70 miles after initial installation the right side bearing failed, one new axle, bearing, and housing later and the other side failed with 86 more miles.

Its been street driven, no brake stands, no sticky tires. its behind a 5.2 auto in a Dakota.

I'm trying to figure out the root cause, so I can avoid it.

I have put many, many 8-3/4's through some rather intense abuse, and never had a failure like this.

The most frustrating part is if I was beating on the thing I could understand it breaking, but that was not the case here.