What is the Difference Between Gear Oil and Engine Oil?
2 Answers
Gear oil and engine oil differ in their performance characteristics: Engine oil primarily focuses on low-temperature performance, maintaining good fluidity in cold conditions; gear oil, on the other hand, emphasizes performance under high temperature and high pressure, as the pressure between gears is much higher than in an engine, and the operating temperatures are also significantly higher. Additionally, engine oil is weakly alkaline, while gear oil is strongly alkaline. Engine oil, also known as engine lubricant, serves to lubricate, clean, cool, seal, and reduce friction in the engine, and is composed of base oil and additives. Gear oil, referred to as transmission lubricant, is mainly made up of antioxidants, antifoaming agents, and rust inhibitors, and is used for lubricating various gears in transmissions, reducers, and differentials to prevent wear and sintering on gear surfaces.
I've been driving trucks for twenty years, and the main difference lies in their purposes. Engine oil serves the engine, dealing with high temperatures and pressures daily, and it also cleans carbon deposits and metal debris, so it has excellent fluidity. Gear oil, on the other hand, deals with the metal components in the transmission and differential, where there's intense squeezing, requiring it to be particularly viscous to form a protective film. The most obvious difference is the replacement intervals—my old truck needed an oil change every 5,000 kilometers, but the gear oil could last up to 50,000 kilometers. Using the wrong one is a no-go; once, I took a shortcut and added engine oil to the transmission, and shifting gears sounded like stepping on gravel with all the grinding noises.
