Abstract: A cooling device for cooling an automatic transmission by forcing air into heat transference with the transmission pan comprising a framework spaced below the bottom surface of the pan to provide a gap for the flow of air and a plurality of slats; each of the slats mounted to the framework at an upwardly inclined angle from front to rear transverse to the length of the pan and in parallel relationship with one another. Each of the slats is provided with an air intake opening, each opening being raised on successive slats from front to rear in "stair-step" fashion for maximum heat transference over the length of the pan. A pair of brackets are provided for mounting the device to existing pans or, in the alternative, the device may be unitary with the pan. The device is particularly useful on all vehicles having adequate ground clearance such as pickups, trucks, motor homes, and the like.