8-3/4 Pinion Nut Torque???

I had a shop put my diff in. Problem is it makes noise at 30mph. Only around 30mph. But it is loud enough to hear over my engine, which is pretty loud.

I went by another garage to day, he said the pinion nut is supposed to be torqued not impacted on. I saw the first garage impact it on. So I'm fairly certain that's what it is.

1 What is the torque supposed to be on the pinion nut of a 8-3/4 with a crush sleeve?

2 How much trouble, or how involved is it to replace the crush sleeve