Heavy or lightweight?
I have always used the Pink/Red heavy stuff. It's $$$$$$ but Hard to beat it.
I like other people strain it when I drain it, then put it right back in and top off with new.
From RedLine
•Film thickness greater than an SAE 75W250, yet low fluid friction like 75W90
•Many performance racing applications like Sprint/Midget/Dirt Late Model Differentials, Detroit Lockers and spools, NHRA Top Fuel and Funny Car rear ends
•Not recommended for most synchro applications due to the product's extreme slipperiness
