Your truck shoud have a trans cooler already, you probably don't have an engine oil cooler as most sports if any at all, come with this. I will almost guarentee you, the transmission has very little to do with engine overheating. Unless your trans temp light illuminates while engine temp gauge climbs. When's the last time you rodded or replaced radiator? Fan clutch? Water pump?
You issue lies more in the engines cooling system. Electric Fans are really good for cooling, and may solve your problem. But I will say, even with a proper cooling motor and wheeling at slow speeds when it's over 100 degrees, may just want to soak up that summer heat. Well maintained vehicles could still struggle with this.
You could always upgrade to electric fans, 3 row or aluminum radiator, add a second pusher fan behind the grill to assist the current condenser fan, wire a switch to consenser fan to help without ac on. This could all really just be covering up an internal engine failure or improper cooling of your current system.
Take baby steps first, replace your radiator cap and thermostat, replace coolant/flush. Replace or have your radiator serviced. Fan shroud, fan clutch, the fan itself maybe?
By the way, the ford fan is the Taurus fan, that and the Volvo fans are beast mode fans, really awesome