Red Line Gear Oils are designed to provide excellent low temperature characteristics and improved gear protection at higher temperatures. Red Line Gear Oils will reduce differential temperatures 10 to 70 Degree Fahrenheit. Efficiency improvements between 1 to 5 Percent are typical. The synthetic base stocks used have tremendous thermal stability and provide the best film strength available. The unique combination of base stocks and additives allow Red Line gear oils to carry higher loads compared to petroleum lubricants. The stability of these products allow them to be used for extended periods. Red Line 75W90 Gear Oil provides excellent protection in nearly all differentials, conventional and limited slip, in both racing and street use. 75W90NS and 75W140NS can be used in certain limited slip units in racing to lock up the differential. 80W140 should be used in commercial hauling, problem limited slip units, racing applications which see tremendous torque at low speeds, and where noise deadening is desired. Lightweight or SuperLight can be used to obtain maximum power transfer in racing differentials which do not see extremely high temperatures. If “chattering” occurs with any of these lubricants, Red Line Limited Slip Friction Modifier can be used to eliminate the stick/slip action and reduce the noise. This additive should not be necessary in the 75W90, 75W140 or the 80W140 Gear Oils, since they already contain this additive, but in some units more is required. Too much friction modifier can reduce the lockup in limited slip units, so it should only be used if needed.