1. Suitable viscosity and good viscosity temperature properties. Viscosity is the most fundamental property of gear oil. The formation of fluid dynamic film and elastic fluid lubrication film is closely related to the viscosity of gear oil. The higher the viscosity of the oil, the thicker the oil film formed, and the greater the ability to resist load. If the viscosity temperature is good, the degree of change in viscosity with temperature is small. The change in oil film thickness is also small.

2. Adequate extreme pressure and wear resistance. Oil products with good extreme pressure and wear resistance will form boundary adsorption films or chemical reaction films under high speed, low speed, heavy load or impact loads of the gear mechanism. It can prevent tooth surface wear, scratches, and bonding.

3. Good oxidation stability and thermal stability. When gear oil is in contact with air, metals, and impurities during operation, it is prone to oxidation and deterioration at high temperatures, resulting in a shortened service life of the oil.

4. Good demulsibility. When gear oil is working, there is often a possibility of contact with water, as oil and water mix and are prone to emulsification and deterioration.

5. Good foam resistance. For the gear transmission system with circulating oil tank, the oil flow is stirred during operation, which is easy to produce foam, thus reducing the actual working oil volume, affecting heat dissipation, or causing oil film damage and increasing mechanical wear.

6. Good rust and corrosion resistance. Oil oxidation products or additives often cause gear corrosion, while the presence of water vapor causes metal corrosion.