Abstract: A hydrostatic backdrive to control conveyor or differential speed in a centrifuge is provided. In a first embodiment, a preselected differential speed is selected by an input to a pump/motor, i.e., a variable volume positive displacement pump. The variable volume pump provides hydraulic drive fluid to a backdrive motor, which drives the conveyor. If solids content of the influent to the centrifuge changes, this is sensed by the backdrive motor, which sends a feedback signal to the variable volume pump to raise or lower its output in response. This way, in the first embodiment, a constant differential speed is maintained. In a second embodiment, the drive on the conveyor is monitored to maintain a constant torque on the conveyor. If solids content of the influent changes, this is sensed by the torque monitor, which sends a signal to the variable volume pump to increase or decrease flow as necessary to maintain that selected torque on the conveyor.