auto trans upgrades for towing

[qtrhors]

Have a 28 ft 5th wheel Im leaving with for Portland Or from Billings Mt. Some grade to deal with My question is what mods have you guys done or like for the auto trans. Now this may sound like a pretty dumb question but does my rig have a factory external tranny cooler?(no I havnt looked yet). What type/size? What should I get? Im thinking a better tranny pan too Suggestions? thanx.

Tim