Is Transmission Oil the Same as Engine Oil?
3 Answers
Transmission oil and engine oil are not the same. The differences between them are as follows: 1. Different properties. (1) Engine oil is the lubricant for the engine. (2) Transmission oil is a lubricant used to keep the gear system clean. 2. Different functions. (1) Engine oil lubricates and reduces friction in the engine, assists in cooling, seals against leaks, prevents rust and corrosion, and acts as a shock absorber. It is known as the 'blood' of the car. (2) Transmission oil ensures the normal operation of the transmission and extends the service life of the transmission components. 3. Different characteristics. (1) The engine is the heart of the car, containing many metal surfaces that rub against each other. These components move at high speeds in harsh environments, with operating temperatures reaching 400°C to 600°C. (2) Transmission oil has anti-low-temperature properties and provides effective lubrication even at low temperatures, reducing oil loss under severe operating conditions.
Transmission oil and engine oil are definitely not the same thing. I’ve learned this from chatting with mechanics a few times. Engine oil is mainly used to lubricate internal engine components like pistons and crankshafts, while also helping with cooling and rust prevention—it’s essentially a protective shield for the engine running at high temperatures all day. Transmission oil, on the other hand, is specifically designed for automatic or manual transmissions, lubricating gears to reduce friction and ensure smooth power delivery. Their compositions are quite different: engine oil tends to be thinner with lots of anti-wear additives, while transmission oil is thicker to handle the stress of frequent gear shifts. Once, a friend of mine made the mistake of pouring transmission oil into the engine, and within days, the machine overheated and started making noises, costing over a thousand dollars to fix. That’s why experienced drivers always remind us to double-check the labels during maintenance—use only what the manual specifies and don’t mix them up for convenience. Otherwise, you’ll damage the car and waste money. Regular oil changes are also crucial: engine oil typically needs replacement every 5,000–10,000 km, while transmission oil lasts 20,000–50,000 km, depending on the vehicle. This knowledge has saved me a lot of headaches.
I always treated this as common knowledge. After working on my own car and repairing it several times, I realized that transmission fluid and engine oil are completely different things. Simply put, engine oil is for maintaining the heart of the engine, lubricating moving parts under high temperatures; transmission fluid, on the other hand, is specifically responsible for gears and clutches, ensuring smooth shifting like silk. When buying oil from the shop, labels with ATF or MTF indicate transmission fluid, while engine oil usually has API grade markings. During my last maintenance, the technician emphasized that using the wrong oil could damage transmission bearings or clog the oil pump, leading to expensive repairs. I generally follow the manufacturer's guidelines—for example, my car uses 5W-30 engine oil and a specialized 75W-90 for the transmission. I’d advise everyone not to believe random rumors about mixing oils. The cost of the fluid itself isn’t high, but the consequences of misuse can be costly. For car maintenance, checking fluid levels regularly can prevent problems before they arise.
