I am new to working on cars and have a few questions maybe someone could answer. I pulled my radiator this weekend to repair leaks and notice it is designed to cool transmission fluid with entry and exit points at the bottom of the unit, water with entry and exit points at the top and bottom of the unit and a second radiator on the far left that appears to cool motor oil with entry and exit points at top and bottom. I do not want to mess anything up and need to know if there are any special instructions I should be aware of in regards to the transmission section and the motor oil section. Do I need to do anything when the unit goes back in aside from topping off fluid levels? Also what is the front radiator for with the aux fan? (which I have never heard go on) Does the aux fan help cool the motor as well?