What is gear oil?

[SanIsabela]

Gear oil is a type of lubricant used in various gear transmission devices. It is primarily composed of petroleum-based lubricating oil or synthetic lubricating oil, blended with extreme pressure anti-wear agents and oiliness agents. Below are specific details regarding the selection of vehicle gear oil: 1. Viscosity grade selection: This is mainly based on the minimum ambient temperature and maximum oil temperature, while also considering factors like oil change intervals, serving as the basis for selecting the viscosity grade of gear oil. 2. Performance grade selection: Generally determined by the type of gears and the function of the transmission device, serving as the basis for selecting the performance grade of gear oil.

[VonCarmen]

Gear oil is a specialized lubricant designed for gear components like transmissions and differentials in vehicles, primarily to prevent dry friction between gears. As someone who drives a manual transmission car regularly, I know firsthand that without this protective oil film, gear shifting would become extremely stiff. Gear oil also aids in heat dissipation, as significant friction-generated heat occurs during gear meshing, and aged oil can't keep up with cooling effectively. Although automatic transmission cars use automatic transmission fluid (ATF), its fundamental function remains gear lubrication. When selecting gear oil, pay attention to the GL rating: GL-4 is suitable for manual transmissions, while GL-5 is designed for high-pressure environments – never mix them.

[DeJordan]

I used to not understand what gear oil was, until a mechanic told me it's like 'protective cream' for gears. Without it, metal gears grinding directly against each other would produce harsh noises and eventually wear out over time. Last time I forgot to change it, I could even feel the clutch pedal sticking. Both manual transmissions and rear axles need it, and while automatic transmissions use different fluids, the lubrication principle is the same. Gear oil comes in mineral and synthetic varieties, with synthetic being more durable but also more expensive. For most family cars, changing it every 60,000 kilometers as per the maintenance manual is sufficient.

[LeErin]

Those who have driven older cars know how crucial gear oil is. With its high viscosity, it forms an oil film during high-speed gear rotation, reducing metal friction and wear. Unlike regular engine oil, gear oil must withstand greater compressive forces, requiring a robust anti-wear formula. Manual transmissions rely entirely on it for lubrication—if the oil degrades, you'll clearly feel rough gear shifting. Automatic transmission fluid serves a similar purpose. Regular car owners should remember to replace it according to the maintenance schedule, rather than waiting for unusual noises or increased fuel consumption. During oil changes, it's best to use a machine for thorough circulation to avoid contaminating the new oil.