[njk53]

I have done a lot of testing on both in-tank cooling and auxilary transmission oil coolers (air to oil) . Depending on the type of coolers used, generally the in-tank unit cools approximately 3-5 degrees cooler than an auxilary air to oil unit. I like the fact that the engine rejects the heat into the radiator and the coolant washes over the in-tank cooler and it heats up the internals of the transmission and the transmission fluid much faster than an aux. cooler. As somonone stated when the transmission is at temperature, you have more consistant cooling of the transmission and fluid with the in-tank unit.