Is There a Difference Between Gear Oil and Engine Oil?

[OMaggie]

Gear oil and engine oil are different, mainly reflected in the following aspects: 1. Different working environments: Gear oil is primarily used in manual transmissions, reducers, and differentials, while engine oil is mainly used in car engines. Since gear meshing involves line contact, gear oil must have extremely high viscosity to form an oil film at the gear meshing points. In contrast, engine lubrication involves mostly surface contact, without the extreme high pressure generated during gear meshing, so its viscosity requirements are relatively lower. 2. Different emphases: Gear oil focuses on protecting gears under high temperatures, while engine oil emphasizes its fluidity at low temperatures. Additionally, gear oil is strongly alkaline, whereas engine oil is weakly alkaline. 3. Engine oil and gear oil must never be mixed, as this can easily prevent machinery from achieving optimal lubrication, leading to damage.

[VanHeidi]

Yes, gear oil and engine oil are indeed different, as I've learned from working on my own car. Gear oil is primarily used in transmissions and differentials, designed to be thicker to withstand high-pressure friction and protect the gear system. Engine oil, on the other hand, is specifically for the engine, with lower viscosity, and besides lubrication, it also helps cool engine components and handle combustion residues. For example, driving a manual transmission car means I need to regularly check the gear oil in the transmission, typically changing it every two to three years; whereas engine oil needs to be replaced every six months, otherwise the engine can overheat and get damaged. Mixing them up can lead to unusual noises while driving and potentially major failures. I remember once helping a friend change his oil, and he almost poured engine oil into the transmission—fortunately, I caught it in time. Always referring to the maintenance manual is the way to go; using the right oil ensures the car runs smoothly and reliably.

[McEden]

Actually, as a car owner, I gradually figured out the difference between the two through daily driving. Gear oil is specifically designed for gears, used in places like manual transmissions, with high viscosity and strong pressure resistance. Engine oil, on the other hand, is used in the engine, focusing more on cleaning and heat dissipation. I was confused at first too, thinking they were the same kind of oil and could be used interchangeably. But one time, when my car's transmission started making strange noises, the mechanic told me it was due to using the wrong oil. Now, during every maintenance session, I pay extra attention: changing the engine oil frequently, roughly every 5,000 kilometers; gear oil lasts longer, only needing replacement every 40,000 kilometers. The benefits are longer component lifespan and reduced repair costs. Here's a little tip: check the oil color—if the engine oil turns dark, it's time to change it; if the gear oil changes color, it also indicates a problem. After forming these habits, my car has become more reliable.

[VanOwen]

In my opinion, the difference between the two is crucial. Gear oil has higher viscosity, making it suitable for gear transmission; engine oil is thinner and designed for engine lubrication. Using the wrong oil can accelerate component wear. For instance, using engine oil in a transmission may cause gears to overheat and fail; using gear oil in an engine can clog the filter. I recommend following a regular inspection and maintenance schedule to avoid such issues.