Rearend Fluid - Synthetic or not?

[Arnold Greene]

Ben, I've used Mobil 1, Red Line, Royal Purple, Castrol Syntec, and Valvoline. I use whatever is available. Right now, I am using RP, but the weight is more important than the brand, IMHO. Don't forget the moly and make sure the rear is warm to keep it in suspension, before you make a hit. Good luck.