When I'm stopped after an hour of highway driving once and a while I hear and feel a fan under the car! I know its a good thing but what exactly is it cooling? the Tranny?

 

It's cooling off the entire engine bay. Shouldn't stay on for more than a couple of minutes, depending on ambient temperature. If you want to be extra kind to the engine, you can lift the bonnet when you get home, as that will cool things off much faster than if the bonnet were left closed. Us trackheads do this after each lap session.

 

Thanks for the quick response! Happy motoring!