Are gear oil and transmission oil the same?

[OJune]

Gear oil and transmission oil are the same. Transmission oil includes manual transmission oil and automatic transmission oil. Manual transmission oil is collectively referred to as gear oil, while automatic transmission oil has a higher grade and is also called drive oil. At the same time, ordinary gear oil cannot be used in automatic transmissions; automatic transmission oil must be used instead. Gear oil is mainly composed of petroleum lubricating base oil or synthetic lubricating oil, blended with extreme pressure anti-wear agents and oiliness agents to form an important lubricating oil. It is used in various gear transmission devices to prevent tooth surface wear, scratches, sintering, etc., thereby extending their service life and improving power transmission efficiency. Gear oil should have excellent anti-wear and load-bearing properties as well as suitable viscosity.

[CooperLynn]

In my many years of repairing cars, I've found that gear oil and transmission fluid are often confused, but they're not the same thing. Gear oil is mainly used for manual transmissions, differentials, or steering systems. It has high viscosity and can withstand high-pressure friction, protecting gears from wear. Transmission fluid, on the other hand, varies by situation: the oil for manual transmissions is similar to gear oil, but the specialized fluid for automatic transmissions, called ATF, is much thinner and contains special additives to control clutches and dissipate heat. Many car owners mistakenly think automatic cars also use gear oil, and using the wrong type can lead to transmission slippage or unusual noises. It's recommended to check fluid specifications during each maintenance and refer to the owner's manual to choose the right product. Remember, manual transmissions require gear oil of GL-4 or GL-5 grade, while automatic transmissions must use the manufacturer-recommended ATF type, such as Dexron or Mercon.

[DelAlana]

Once I went to chat with a friend at his car shop. His old manual transmission car used so-called transmission fluid, which was actually just regular gear oil, and it turned out fine. But he said it would have been disastrous if it were an automatic transmission car. Gear oil in a manual transmission is essentially gear lubricant—it's thick in viscosity and has high anti-wear properties. Transmission fluid in an automatic car, on the other hand, is a low-viscosity liquid designed for circulation and heat dissipation. Why do people confuse them? Mainly due to language habits: in daily conversation, we might refer to gear oil in a manual transmission as 'transmission fluid,' but automatic transmission fluid (ATF) is entirely different. Since buying my car, I've always followed the manual's instructions—changing gear oil every 3-5 years for manual models and replacing ATF more frequently for automatic ones, which saves both hassle and repair costs. Regularly check the fluid level and color; if it discolors or has particles, it's time for a change.

[GraceLee]

Simply put, gear oil is not the same as transmission fluid. Gear oil is specifically designed for gear mechanisms, such as the gearbox in a manual transmission, and has a high viscosity to protect the gears. Transmission fluid, on the other hand, might be used in manual transmissions, but automatic transmissions use ATF (Automatic Transmission Fluid), which has a lower viscosity suitable for precision components. Do not mix them, as their viscosity differs significantly: gear oil is thick and heavy, while ATF is thin and light. Using the wrong oil in a manual transmission can accelerate wear, and using gear oil in an automatic transmission can cause clutch failure. As a new driver, I recommend first checking your vehicle type: for manual cars, refer to the GL-4 gear oil specification, and for automatic cars, choose the specified ATF. For routine maintenance, check the fluid every two years.