Transmission sump level control system

A method of controlling a level of fluid in a main sump of a transmission having a pump for controlling flow of the fluid inside the transmission, the method comprising:

• opening via a controller fluid communication between an auxiliary reservoir and the main sump by opening an active first valve when a temperature of the fluid inside the main sump is at or below a predetermined temperature;
• and
• closing via the controller the auxiliary reservoir by closing the first valve, such that, when the transmission is transmitting torque and the fluid is above the predetermined temperature, the level of the fluid in the main sump is maintained below a predetermined height and rotating components of the transmission do not contact the fluid inside the main sump;
• wherein the opening of fluid communication between the auxiliary reservoir and the main sump causes a level of the fluid in the main sump to increase to at least the predetermined height;
• wherein the rotating components of the transmission contact the fluid inside the main sump to generate splash lubrication of the rotating components;
• wherein the auxiliary reservoir is configured to hold at least a portion of the fluid and the first valve is configured to selectively open and close fluid communication between the main sump and the auxiliary reservoir;
• and
• wherein the pump alone is sufficient to lubricate the rotating components above the predetermined temperature and sufficient to lubricate the rotating components at or below the predetermined temperature only with the splash lubrication.