Originally Posted by ConroeJK

I'm no mechanic, but lucky you, I bored so here's the basics.

Auto transmissions pump their fluid, usually, through a portion of the radiator to cool it and maintain proper running temps. When the transmission is working hard, i.e. shifting often, towing, rock climbing, etc, temps climb and the engine radiator is working primarily to cool the engine coolant which is also running hotter during these conditions. Tranny cooling becomes less efficient.
A aux cooler is simply a separate radiator for the tranny fluid, normally mounted in front of the engine radiator. It is almost always included in a vehicles "tow package", the JK is the exception of course.

Originally Posted by Mikey214

thanks ! i appreciate the information!

Originally Posted by Ecb12

Just did this today. Thanks to the OP for a great write up.

Originally Posted by wallawallaron

+1, Question on the Temp. gauge mine is just left of mid-point,can someone tell me what the approximate temp. would be.
Thanks
WWR

Originally Posted by ronjenx

Are you asking about the engine water temp gauge?