What is the Difference Between Transmission Fluid and Engine Oil?
2 Answers
Theoretically, engine oil and transmission fluid serve the same primary functions, including lubrication, cleaning, rust prevention, and heat dissipation. The differences between them lie in viscosity and the temperatures they can withstand. Engine oil is used for the normal operation of the engine, enduring the highest temperatures and having the lowest viscosity, while transmission fluid is used for the transmission, withstanding lower temperatures and having a higher viscosity than engine oil. The specific differences are as follows: 1. The Role of Transmission Fluid: The main function of transmission fluid is to keep the car's gear system clean, providing lubrication and cooling. It's important to note that during driving, the gears operate at high speeds, generating heat through friction. At this point, transmission fluid is needed to lubricate and reduce temperature, ensuring the vehicle operates normally. 2. The Role of Engine Oil: Engine oil primarily lubricates the engine system, providing lubrication, cooling, sealing to prevent leaks, rust and corrosion prevention, as well as shock absorption. The condition of the engine oil can directly affect the performance and lifespan of the engine, making it a crucial automotive consumable. Therefore, car owners should pay special attention to the use of engine oil in daily maintenance.
When I first bought a car, I was also confused—transmission fluid and engine oil are completely different things. Transmission fluid is specifically for the transmission, where gears rotate with high friction and require lubrication and heat protection. For automatic transmissions, the fluid also handles hydraulic shifting, so it has a longer replacement interval, typically every 30,000–40,000 kilometers. Engine oil, on the other hand, is for the engine, lubricating internal components like pistons and cylinders to reduce wear and cool the engine, requiring more frequent changes—usually every 5,000–6,000 kilometers. Using the wrong fluid can cause serious trouble: adding the wrong transmission fluid may lead to gear slippage or failure, while neglecting oil changes can cause engine overheating and failure. Always check your vehicle’s manual when selecting fluids—automatic and manual transmissions require different types, and mixing them to save money can damage your car. Regular maintenance saves hassle and costs, preventing breakdowns on the road.
