A power transmission apparatus comprising planetary gear elements for controlling the direction and speed of power transmitted to a driven power unit, such as a vehicle, industrial machines, household equipment, or the like. In one embodiment of the invention, power from a constant speed, uni-directional prime mover is converted to multi-speed forward and reverse power by controlling only the movement of the planetary carrier. In a variation of this embodiment of the invention, a variable speed uni-directional prime mover is converted into a speed division torque-multiplication system by control of the carrier by a torque control device, such as a torque converter, or mechanical torque limited. In yet another embodiment, control of the carrier and associated clutch mechanisms permits one of two output power paths from the transmission to be reversed while the first path continues to rotate in the same direction as the prime mover.