An automatic automotive transmission casing has a shape of a rectangular box with side dimensions: 40 cm x 30 cm x 50 cm. During a long drive, the transmission receives a mechanical power input from the engine at a rate of 100 kW. Approximately 20% of the received power is dissipated due to internal inefficiencies of the transmission. During this operation, the outside air beneath the undercarriage, at temperature Ta =: 30 OC flows around the transmission casing, effectively cooling it. If the convective heat transfer coefficient is equal to ha= 200 W/m2 K, calculate the surface temperature of the transmission casing.