On my V730 (which is a HT740 without 1st gear) I added an auxiliary trans cooler with a built in electric fan actuated by a thermostatically controlled switch with manual override. It is plumbed where the hot oil comes out of the transmission, goes first through the auxiliary trans cooler, then through the stock shell cooler then back to the engine. This way, the auxiliary cooler takes a lot of the heat out before hitting the standard cooler that is cooled by the radiator, keeping a lot of heat away from the radiator. Also, on cold days the standard cooler actually heats up the transmission faster then if it didn't have it. It can be just as bad running an engine or transmission too cold as running it hot. Good Luck, TomC