Gear Oil, 75W90, Red Line Synthetic, 1 Quart Bottle (2 Bottles Required)P N 57904 Red Line's 75W90 Synthetic Gear Oil is their most popular gear oil, and is the preferred product in nearly all car and light truck differentials, both conventional and limited slip. 75W90 is preferred for most racing applications. It contains friction modifier which is recommended for limited slip units. 75W90 Gear Oil can be used in many transmissions and transaxles. However, other Red Line lubricants have better frictional properties for