I want to replace my 1978 R&P flanges with multi-hole aftermarket flanges.

My R&P are set up with 488 gears and crush sleeves. The gears are still great after years of abuse. Now the sleeve crushes during setup till you get the right mark on the ring gear. I remembered this takes alot of torque. Can you just change to a new flange with this setup without pulling the third and verify setup. My apologies it this a bonehead question, I can not remember.

Karl

The crush sleeve is for setting the preload on the pinion bearings and doesn't have anything to do with the pinion depth or tooth contact pattern. It is designed to be an easy way to set the preload, but the problem is that you need to replace it with a new crush sleeve when you change flanges and need to set the preload again. In an emergency, I would just tighten the nut until you get the same overall preload in the diff as before (something like 22 inch pounds), but I wouldn't want to run it that way for long. Either get a new sleeve or set it up with preload shims.