A steering transmission transmits steering forces that must be transmitted from a steering mechanism, such as a steering wheel or handlebars, to a steered mechanism, such as the rudder of a boat or the steered wheel(s) of an off-road vehicle. The steering transmission includes one and preferably both of a multi-ratio speed changer and a torque gate. The multi-ratio speed changer preferably takes the form of one or more planetary gear sets coupling an input shaft of the transmission to a rotary output of the transmission. The speed changer is shifted by manually operating a shifter to switch between two or more distinct speed change ratios, thereby permitting the operator to select the combination of responsiveness and steering effort desired for the prevailing operating conditions. The torque gate preferably takes the form of a release driver, a locking driver, and a wrapped spring disposed between the release driver and the locking driver. The spring moves relative to a housing or other stationary surface upon the transmission of steering forces to the clutch from the steering mechanism but grips the stationary surface upon the imposition of external backdrive forces on the steering system so as to prevent the transmission of those forces back to the steering wheel and other upstream components of the steering system.

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