Just remember - if you use the in-tank cooler that's part of a radiator spec'd for an auto-tranny car, you're basically using the radiator coolant to cool the other fluid. Whether an oil cooler, or tranny cooler, I prefer to have the coil for that in separate air flow than the air flowing over the radiator and a/c condenser (e.g. - under the car) so that all the capacity of the radiator can be used for dealing with the engine's coolant. Also, has anyone actually switched the tranny cooler over to be an engine oil cooler? I've wondered about it - what kind of pressure is the tranny fluid under? Is it comparable to the 50-70 psi the oil will produce? Just curious if the tranny cooler is rated for that or not.