Red Line MTL is a 75W80 GL-4 gear oil (SAE 5W30/10W30 engine oil viscosity) designed for use in manual transmissions and transaxles. MTL is a low 75W at very low temperatures, and a high 80W, nearly an 85W, at elevated temperatures, providing adequate viscosity to prevent wear and deaden gear noise. Overall, this gear oil provides excellent protection of gears and synchronizers, and its balanced slipperiness provides a perfect coefficient of friction, allowing easier shifting.