The present disclosure provides a method for increasing a volume of hydraulic fluid in a reservoir of a transmission. The method includes providing a retarder mounted to the transmission, an accumulator including an internal cavity, a piston disposed in the internal cavity of the accumulator, a solenoid, a valve, and a controller. The method also includes enabling the solenoid from an off state to an on state, transferring fluid pressure from the valve to the piston, and moving the piston from a first position to a second position in the internal cavity. The method further includes discharging an amount of hydraulic fluid from the internal cavity of the accumulator to the reservoir and increasing the volume of hydraulic fluid in the reservoir.