You’ve added this the the 10r80 with success?Should be 3-ish for the rear
I’m using same fluid, Amsoil gear oil is great stuff, their ATF makes a noticeable improvement in shift feel every time I swap it out on my manual trans C5Z (yeah sounds odd but Amsoil recommends their synthetic ATF for the Tremec T56) - which made me a real believer in their stuff (on top of engine oil analysis always coming back clean)