A motorized drum has a drum shell, and a motor and a cycloidal reducer, are disposed inside. An output of the reducer rotates slower than the motor, and a hollow input shaft accommodates miscellaneous components. The hollow input shaft has an eccentric raceway that engages an input gear of the cycloidal reducer, and urges it into eccentric motion. The cycloidal reducer has an internal toothed output ring gear that is rotationally affixed to the drum shell for transmitting rotary power thereto. A fixed shaft is coupled to a guide pin housing that constitutes a fixed reference point of the cyclo reducer. A torque coupler has orthogonally placed driving face pairs that couple the guide pin housing to the fixed shaft. The hollow input shaft has plural axially protruding driven tabs for receiving an input torque from the motor rotor. A coupler has orthogonally arranged driven face pairs for coupling the hollow input shaft to the motor rotor.