Can 85w140 Gear Oil Be Used in a Transmission?
2 Answers
85w140 gear oil can be used in transmissions. 85w140 gear oil is a multi-grade viscosity, all-weather type with a wide operating temperature range, making it suitable for year-round use. In 85w140 gear oil, the 'w' stands for winter-grade gear oil, '85' indicates the low-temperature viscosity—the smaller the number, the lower the viscosity, resulting in better low-temperature fluidity and performance. '140' represents the high-temperature viscosity—the larger the number, the higher the viscosity and temperature resistance. Gear oil is primarily composed of petroleum-based lubricating oil or synthetic lubricating oil, blended with extreme pressure anti-wear agents and oiliness agents. It serves to lubricate gears and bearings, prevent wear and rust, and assist in heat dissipation for gears. It is used in various gear transmission devices to extend their service life and improve power transmission efficiency.
The viscosity grade 85W140 is quite high. The number before the W represents low-temperature fluidity, and the number after it indicates high-temperature viscosity. For ordinary family cars, it's recommended to use medium-viscosity oils like 75W90 or 80W90 in the transmission. 85W140 is too thick. During cold starts in winter, the oil won't flow properly, leading to insufficient lubrication of transmission gears and accelerated wear. Automatic transmissions require extra caution, as ATF (Automatic Transmission Fluid) demands specific friction coefficients. Using excessively high-viscosity oil can cause clutch plates to slip and significantly increase shift shock. I once saw someone use this oil in a manual transmission car, and it became difficult to engage first and second gears, with fuel consumption rising by 10%. It's advisable to check the recommended grade in the owner's manual rather than experimenting arbitrarily.