Abstract: A power take off device includes input and output shafts and an integral planetary gear set. The power take off device may be a single speed or a two speed device. The input shaft and the output shaft are mechanically connected through the planetary gear set. In one mode of operation of the power take off device, a substantial speed reduction and torque increase is provided between the input shaft and the output shaft. The power take off device may change to a second mode of operation without stopping to provide a direct one to one speed and torque ratio between the input shaft and the output shaft. A planetary gear set clutch unit includes a two direction actuator that provides fluid pressure actuation and release of the clutch unit with a single input signal.

Abstract: A system and method of dithering speed and/or torque for shifting a transmission of a vehicle having an engine, a reversible, variable displacement hydraulic motor/pump which can be driven by the engine, a hydraulic accumulator supplied by said motor/pump, and at least one reversible hydraulic driving motor for propelling the vehicle supplied with fluid by the hydraulic accumulator and/or by said motor/pump operating as a pump. A transmission unit connects the engine with the variable displacement hydraulic motor/pump during a first mode of operation (city mode) and connects the engine to a vehicle drive wheel during a second mode of operation. The system utilizes stored hydraulic energy to dither the output of the driving motor in order to achieve quick and smooth shifts between city and highway mode, or between various ranges within the city mode.