Therefore, it has a very high sulfer and phospor content. Sulfur and Phosphate reactions start at a lower temperature, and Gear Oil has much more additive than motor oil. This additive is corrosive to copper bearings and bronze synchro rings. Positraction additives are Friction modifiers - make the base oil much more slippery. Friction Modifiers may detract from EP characteristics.
Friction modifiers cause smooth take-up of Limited slip units.
For track racing, FM is probably undesireable, and immediate take-up is more important. For Street, FM is usually reccomended for more comfortable operation. Hypoid type gear sets have a sliding rather than rolling action, and therefore require much greater wear protection. Should be used in rear differentials. Used for heavy trucks and Tow Vehicles.