Is Engine Oil the Same as Transmission Fluid?
2 Answers
Engine oil and transmission fluid are not the same. The difference between them lies in their functions: engine oil is the lubricant for the engine system, possessing certain properties such as oxidation resistance, wear resistance, and corrosion prevention. Transmission fluid, on the other hand, is primarily used to keep the gear system clean, ensuring the transmission operates properly and extending the lifespan of the transmission components. The method for changing transmission fluid is as follows: 1. Start the engine to preheat the transmission to operating temperature; 2. Remove the drain plug; 3. After draining the old fluid, reinstall the plug; 4. Add new transmission fluid; 5. Start the engine, shift from P to N, D, L1, and L2 repeatedly, staying in each gear for at least 5 seconds; 6. Check if the automatic transmission fluid level is normal.
I think engine oil and transmission oil are completely different. From my experience, engine oil is specifically designed for the engine, lubricating pistons and bearings under high temperature and pressure, while also dissipating heat and preventing carbon deposits. Transmission oil, on the other hand, is tailored for gearbox gears and hydraulic systems, ensuring smooth shifting and wear resistance. Their formulations differ: engine oil adjusts viscosity quickly and contains detergents, while transmission oil requires stable viscosity and strong anti-wear properties. Their replacement cycles also vary—engine oil needs changing every 5,000 kilometers or so due to contamination buildup, whereas transmission oil lasts longer, requiring replacement around 40,000 kilometers. Mixing them up can cause major issues, such as accidentally adding engine oil to the transmission, leading to hydraulic failure or gear damage. I’ve seen a friend’s car incur thousands in repair costs because of this. During daily driving, regularly check the oil’s color and texture—if it turns black or feels gritty, address it promptly for safety. Always refer to the vehicle manual and choose the right oil type for the season.
