The development of the automobile industry has promoted the progress of lubricant for automobiles. The increase of truck load makes the power of rear axle gear drive increase, and the geometrical size of the latter axle gear is not changed greatly, which leads to the increase of tooth surface pressure, which requires more bearing capacity of the vehicle gear oil. Car body design continuous improvement, so that the aerodynamic performance more reasonable, the car when the air resistance decreases, flow through the surface of the rear axle housing to reduce air flow, heat dissipation can be worse, gear oil heat load increase, which requires gear oil has better thermal oxidation stability. Foreign car manufacturers will increase the insurance of rear axle and gearbox equipment to 1. 2x10 ' km, in connection with this, requires increased vehicle gear oil life. GL-5-type vehicle gear oil has been born for nearly 30 years, in this 30-year gasoline engine oil has been updated for 4 generations. In the late 80, the American Association of Automotive Engineers (SAE), the American Institute of Materials Testing (ASTM) and the American Petroleum Society (APL) began to consider the issue of replacement of vehicle gear oil, and presented two agreed specifications Pg-l and PG-2. Pg-l is used for manual transmissions of heavy vehicles, PG-2 will replace GL-5.