I am in the process of changing out the syn. gear oil in the rear axle with Amsoil syn. 75-90 severe gear oil and my neighbor informs me that I need to use an additive as well for limited slip diffs. I am at a stand still here as I can't seem to find any info about this. The Amsoil bottle does say"use their additive if gear chatter results". Anybody have an answer for me? 05'Duramax with Allison tranny 4X4. :help:

Tell your neighbor to shut his pie hole ):h
You don't need any additive, just 75w-90 gear oil

Thanks Partsguy. I needed that.....