what a stupid thing to do

I have used both the crush sleeve and the eliminator. I have never had any issues with the crush sleeve. Kind of sounds like he over tighten the pinion nut. There is a rule of thumb when reusing a crush sleeve is tighten it an extra 1/4 of a turn. That is why he indexed it. I don't like to reuse a crush sleeve period but some time you have to. Don't have to worry about that with the crush sleeve eliminator. The best way to learn is by experience, I build 3-4 diffs a week for the past 20 years.