Red Line GL-5 gear oil has been engineered to provide the highest degree of protection and improvement of your differential efficiency. Formerly Lightweight gear oil, this new formula contains additional friction modifiers for suitability with clutch-type limited slip differentials, and for most, no additional friction modifiers would be required. This gear oil offers excellent lubrication, a high viscosity index, and the ability to lower operating temperatures, as well as exceeding API GL-5 specifications. Reduce friction for better performance--add the improved formula of Red Line GL-5 gear oil.