Abstract: A transmission device for providing positive geared, constant mesh, variable speed, rotary power transmission. The device includes a power drive shaft with an axially mounted, slidable drive gear. This drive gear is locked in rotational movement by means of an axial guide track fixed to the power drive shaft. A transmission drive shaft is fixed in oblique orientation with respect to the power drive shaft and carries a plurality of reduction gears of decreasing radius. The reduction gears are mounted on the transmission drive shaft on a spherical mounting race which permits the reduction gear to have an axis of rotation oblique to the axis of the transmission drive shaft and parallel with the axis of the power drive shaft. The spherical mounting race includes projections which are housed in elongated recesses within each reduction gear.