What does gear oil 85w140 mean?
2 Answers
Gear oil 85w140 indicates that the gear oil is a multi-grade oil with two grades, 85w and 140, suitable for ambient temperatures ranging from -26°C to +50°C. In 85w140 gear oil, the 85 represents the low-temperature viscosity—the smaller the number, the lower the viscosity, resulting in better low-temperature fluidity and enhanced low-temperature performance. The 'w' stands for winter-grade gear oil. The 140 denotes the high-temperature viscosity—the larger the number, the higher the high-temperature viscosity, allowing it to withstand higher temperatures. Gear oil primarily refers to the lubricating oil used in transmissions and rear axles. It differs from engine oil in terms of usage conditions, composition, and performance characteristics. Gear oil mainly functions to lubricate gears and bearings, prevent wear and rust, and assist in dissipating heat from the gears.
The 85W140 gear oil refers to its viscosity characteristics based on the SAE standard. 85W indicates that the oil is relatively thin and flows easily in cold winter conditions, ensuring smooth and effortless cold starts. The 140 represents that the oil becomes thicker at high temperatures, providing strong protection under high-load gear conditions. This combination is particularly suitable for trucks, SUVs, or off-road vehicles, especially in areas with significant temperature variations. I've seen many car owners use the wrong oil in extreme weather, leading to gearbox noise or wear, so it's important to choose oil based on the environment and the owner's manual. Regular gear oil changes are also crucial—typically, inspect it every 50,000 kilometers to avoid performance degradation due to impurity buildup. Don't skimp by using generic oil; matching the requirements ensures your vehicle runs longer and more reliably.
