I'm currently using Dash Command one my phone ,which I have mounted on the dash to keep an eye on everything every time I drive. Very useful tool.
Just wish I knew more about how to use it.

 

A little more in depth than you`ll need but you`ll get the idea. pretty much any auto parts store cooler will work

 

Make sure when buying an external cooler to get the plate type and not the tube and fin type. Get a cooler as big as you can fit in your application. 170-190 is ideal on highway. The temp will raise in town stop and go traffic. Heat and poor maintenance are the #1 factors in transmission failures. Good luck!