Abstract: The invention is directed to apparatus and a method for controlling temperature of lubricant contained in, but not limited to, a differential housing. The apparatus includes a cover plate having an air duct arrangement that includes an intake manifold, a discharge and at least one air conduit that extends between the intake manifold and the discharge. The air conduit communicates with the outside surface of the cover plate, and a temperature responsive fan selectively forces air into the manifold to create an airflow along the air conduit. Heat is transferred from the cover plate surface to the air as the airflow moves through the air conduit and the heated air is expelled at the discharge to lower and control lubricant temperature.