Hoc spiramGERMENTUMSet erat in tractor. In tractor, quod sita est in fronte de driving rota et post tergum Gearbox. All the transmission mechanisms and shells are called the rear axle, and its main function is to step up, increase, decelerate and change the torque .In addition to tractors with transverse engines that use cylindrical gear pairs as central transmission, most of them use bevel gear pairs, which not only increase torque and reduce speed, but also change torque transmission.