A transmission for a marine propulsion system uses a cone clutch in such a way that, when in a forward gear position, torque is transmitted from an input shaft, or driving shaft, to an output shaft, or driven shaft, solely through the cone clutch. When in forward gear position, driving torque between the driving and driven shafts is not transmitted through any gear teeth. When in reverse gear position, torque is transmitted through an assembly of the bevel gears.