Abstract: A freewheel device for connecting a power input to a selected one of a plurality of outputs so as to transmit rotary motion in one direction of rotation and to over-run when the speed of the selected one of the outputs exceeds that of the input, includes a neutral condition in which the input is rotationally disengaged from any of the outputs. In a described embodiment, the freewheel device comprises a plurality of rollers retained circumferentially adjacent one end of an axially movable shaft in operative association with a plurality of wedge-shaped portions formed on the shaft, axial movement of the shaft serving to engage the rollers between the wedge-shaped portions and, selectively axially spaced-apart internal, cylindrical surfaces formed on each of the outputs and on a rotatable support.The freewheel device finds particular application in the transmission system of multi-engined helicopters.