Abstract: A power drive system for a sliding door on a motor vehicle includes a guide track fixedly secured to the vehicle. A motor fixedly secured to the track is adapted to receive power. The motor converts the power into a rotational force. A set of pulleys and wheels are fixedly secured to the track to direct the path of a belt. The belt extends between first and second ends which are operatively coupled to the door and move relative to each other as the motor drives the belt to move the door between open and close positions. Upon manual movement of the door, relative movement between the first and second ends of the belt is sensed by sensors. The sensors create a feedback signal received by an electronic controller which operates the motor to overcome a motor back-driving force and belt friction forces created during manual movement of the door.