This 70W80 GL-4 Gear Oil (SAE 5W30/10W30 engine oil viscosity) is designed for use in manual transmissions and transaxles. Provides excellent protection of gears and synchronizers and its balanced slipperiness provides a perfect coefficient of friction, allowing easier shifting. Popular in many BMW transmissions and in most Honda and Acura transaxle applications. MTL is the correct product for Big-Twin primary chaincase. Big-Twin transmissions should use Red Line Heavy Shockproof, while Sportster and Buell Tranmission should use Red Line 75W90 GL-5 gear oil.