Abstract: A system for use in connection with an automatic transmission of a motorized vehicle is disclosed. The system includes an accumulator which is sealed except for two openings therein. The accumulator is positioned above an operational fluid level of the transmission, with the openings pointing downward. One of the two openings couples to a high pressure fluid line, which extends between an automatic transmission and a heat exchanger. The other of the two openings couples to a low pressure fluid line, which extends between the automatic transmission and the heat exchanger. When the vehicle's motor operates, a pump within the automatic transmission pressurizes these two fluid lines and causes transmission fluid to fill the accumulator. When the vehicle's motor does not operate, the pump does not operate, and the fluid lines depressurize. The depressurizing causes fluid to drain from the accumulator and overfill the transmission.