With the fast development of national highway,the demand is growing stronger on multi-speed transmissions in Heavy-duty vehicle market. In 2002 the company introduced a multi-speed transmission MPT21B design and manufacturing technology, established a multi-speed gear box design platform. In order to meet the market for multi-file demand for high torque gearbox, we designed the DC9J150T, DC12J150T gearbox .In the design of the new products, we used more new technologies on forced lubrication, oil cooling. I...