How to Classify Automatic Transmission by Different Actuation Forms?

The automatic transmission can be divided into two types of rear drive and front drive according to different ways of actuation. Both are greatly different in structure and layout.

The input shaft and output shaft of torque converter and gear transmission in rear drive automatic transmission are on the same axis, therefore the axial dimension is larger; its plate of valve is placed in the oil pan below the gear transmission. The front drive except the same components as the rear drive automatic transmission, but is also equipped with differential in the gearbox differential housing. Car engines in the front drive vehicles are able to be vertical or horizontal mounted. Front drive automatic transmission of engine in vertical placement is basically the same structure and layout with the rear drive transmission, but add a differential in the back.

Front drive automatic transmission of engine in horizontal placement requires a smaller axial dimension for limiting on vehicle lateral dimensions, so its input shaft and the output shaft are typically designed into two axes, to arrange input shaft of torque converter and gear transmission upside and the output shaft is in below. This design reduces the overall axial dimension of the transmission, while increases the transmission hight, therefore mounting the plate of valve on the side or top of the transmission to ensure that the car has the minimum ground clearance.