Truck in sig recommends 4oz of limited slip additive in the rear differential, which from my research, Valvoline Synpower already has mixed in it Total capacity is 2.5 qts Should I go with the valvoline? For a few bucks more, I can get Redline 75w140, does this already have the limited slip additive in it? Any experiences from anyone for either product or another product? Redline: https://www.amazon.com/Red-Line-579...
Valvoline: https://www.amazon.com/Valvoline-75... 560500259&s=gateway&sr=8-2-fkmr1
Also: Any Schaeffers reps on here know if they do or eventually are going to come out with a 75w140?