Just learned something new today. For those who have the locking rear differential and have to pay $50/quart + shipping for diff fluid, you may want to check out Amazon for AC Delco/GM part number 92184900. Looks to be the same Castrol SAF Carbon Mod fluid which is used by Pontiac G8s, Chevy Camaros, and perhaps some BMWs in their diffs. Current price is about $22/liter. Joy!

 

Or you can use Royal Purple

 

This.

 

Sorry for resurrecting an old thread but I was searching for diff fluids for the rear locker and came upon this... can the Royal Purple with the friction modifier be used in our rear diffs? Or is the LR fluid somehow different?
Thanx...

 

Amsoil recommends their 75w90 Severe gear for it, which is what I just put in.