Process of gear steel in China meet the national requirements and the introduction of domestic demand and heavy vehicle driving gear and steel for heavy duty truck rear axle gears, has yet to be developed and produced. Based on the analysis of current situation of domestic heavy trucks using technology, overloading and poor road conditions, the two problems are more serious, and it cannot be overcome in the short term, which makes gear often overload under impact loading. Overloads between the impact load of fatigue and stress, it has a great influence on gear life, often resulting in gear early failure. From this point, the large module, heavy duty automotive gear you should choose Cr-Ni or Cr-Ni-Mo steel, such as Germany's 17CrNiM06 steel is best, and made 20CrNi3H, 20CrNiMoH steel. Contributed to the advent of high-power engines of new Cr-Ni-Mo series gear steel development and application. New type of gear steel 20CrNi2Mo, 17CrNiM06. Faw car company has developed a new truck bridge, which features match the engine's power.