A pump system (100, 200, 300, 400, 500) comprising: a closed-loop fluid circuit comprising: a motor (218, 318, 318', 418, 518) for rotating a first component connected to the closed-loop fluid circuit; and a closed-loop pump (212, 312, 312', 412, 512) for driving the motor at a first rotational speed; an open-loop fluid circuit comprising an open-loop pump (210, 310, 310', 410, 510) for driving a second component connected to the open-loop fluid circuit that provides an auxiliary function; and a control circuit (280, 380, 380', 480, 580) comprising: a control valve for selectively connecting the open-loop pump to the closed-loop fluid circuit while simultaneously disconnecting the open-loop pump from the open-loop fluid circuit, wherein when the open-loop pump is connected to the closed-loop circuit, the closed-loop pump and the open-loop pump drive the motor at a second rotational speed greater than the first rotational speed; wherein each of the closed-loop pump and the open-loop pump comprise variable displacement pumps, wherein the pump system further comprises a controller connected to each of the closed-loop variable displacement pump, the open-loop variable displacement pump, the motor, and the control valve; characterized in that said first rotational speed of the motor (218, 318, 318', 418, 518) is a first maximum rotational speed, and said second rotational speed of the motor is a second maximum rotational speed; the controller is configured to send a control signal to actuate the control valve so as to connect the open-loop variable displacement pump to the closed-loop fluid circuit when the controller receives a first component speed signal corresponding to a desired first component speed that is in excess of a first component speed produced when the closed-loop variable displacement pump is at the first maximum rotational speed; and the auxiliary function of the open-loop fluid circuit is configured to be disengaged, prior to actuating the control valve to connect the open-loop variable displacement pump to the closed-loop fluid circuit. a closed-loop fluid circuit comprising: a motor (218, 318, 318', 418, 518) for rotating a first component connected to the closed-loop fluid circuit; and a closed-loop pump (212, 312, 312', 412, 512) for driving the motor at a first rotational speed; a motor (218, 318, 318', 418, 518) for rotating a first component connected to the closed-loop fluid circuit; and a closed-loop pump (212, 312, 312', 412, 512) for driving the motor at a first rotational speed; an open-loop fluid circuit comprising an open-loop pump (210, 310, 310', 410, 510) for driving a second component connected to the open-loop fluid circuit that provides an auxiliary function; and a control circuit (280, 380, 380', 480, 580) comprising: a control valve for selectively connecting the open-loop pump to the closed-loop fluid circuit while simultaneously disconnecting the open-loop pump from the open-loop fluid circuit, wherein when the open-loop pump is connected to the closed-loop circuit, the closed-loop pump and the open-loop pump drive the motor at a second rotational speed greater than the first rotational speed; a control valve for selectively connecting the open-loop pump to the closed-loop fluid circuit while simultaneously disconnecting the open-loop pump from the open-loop fluid circuit, wherein when the open-loop pump is connected to the closed-loop circuit, the closed-loop pump and the open-loop pump drive the motor at a second rotational speed greater than the first rotational speed; wherein each of the closed-loop pump and the open-loop pump comprise variable displacement pumps, wherein the pump system further comprises a controller connected to each of the closed-loop variable displacement pump, the open-loop variable displacement pump, the motor, and the control valve; characterized in that said first rotational speed of the motor (218, 318, 318', 418, 518) is a first maximum rotational speed, and said second rotational speed of the motor is a second maximum rotational speed; the controller is configured to send a control signal to actuate the control valve so as to connect the open-loop variable displacement pump to the closed-loop fluid circuit when the controller receives a first component speed signal corresponding to a desired first component speed that is in excess of a first component speed produced when the closed-loop variable displacement pump is at the first maximum rotational speed; and the auxiliary function of the open-loop fluid circuit is configured to be disengaged, prior to actuating the control valve to connect the open-loop variable displacement pump to the closed-loop fluid circuit.