Also here is a little speel that the site I get my tranny parts from has posted: "Transmission Cooling: You must have a transmission cooler in your radiator regardless of what someone has told you for the transmission to last. Auxiliary coolers are just that, in addition to. Water cools 32 times better (faster) than air always, period. The transmission fluid comes directly from the torque converter at a much higher temperature than the water in your radiator and is cooled to the water temperature fast. Then it goes to the auxiliary cooler to be cooled far below the water temperature. If you don't need a cooler in your radiator why does Ford spend all that money doing so? If you wanted to cool a red hot piece of steel fast would you stick it in water or air, see the point. For the best cooling you need both water and air cooling for the transmission to be cooler than the motor." Most automatic transmissions fail due to a breakdown of the transmission fluid caused by overheating. This chart provides a graphic display of heats contribution to transmission failure. The effect is also cumulative. Short term exposure to high heat levels (or even prolonged exposure to moderate heat) can break down the fluid to the point where even very short episodes of overheating will lead to failure.