A planetary gear assembly comprising: a housing, which contains: a planetary carrier, a sun gear, at least one planetary gear, a ring gear, a coil spring; an input shaft; and an output shaft. The coil spring extends around at least a portion of the planetary carrier. The coil spring includes a first tang in communication with the ring gear and a second tang in communication with the housing. When torque is applied to the input shaft, the planetary carrier rotates within the coil spring in one or more driving directions so that torque is transferred to the output shaft. When no torque is applied to the input shaft and torque is applied to the output shaft, the coil spring constricts and provides sufficient contact force to the planetary carrier and housing to prevent the planetary carrier from moving relative to the housing in at least one of the driving directions.