Abstract: A housing supports input and output shafts disposed at right angles, and the shafts are connected by a set of reduction gears and a spring biased clutch sleeve splined to the output shaft for axial movement. An electric motor is flange mounted on the housing and has a motor shaft connected to the input shaft which is surrounded by an electrically actuated brake effective to brake the input shaft to the housing. A shift lever operates a control shaft which extends into the housing parallel to the output shaft, and the control shaft supports a rotary cam which moves a spring biased clutch yoke for shifting the clutch sleeve between positive engaged and disengaged positions with respect to a drive gear rotatably supported by the output shaft. The rotary cam provides for spring biased overtravel of the lever operated control shaft and over center action between the engaged and disengaged positions.