The optimum functional location for efficiency should have the coolant flow in series between the cool outlet of the radiator and the thermostat inlet. That way the temperature of the coolant would be around 150 deg. F. For that location the coolant inlet and outlet ports should be comparable in diameter to the radiator ports to prevent flow restriction. I suspect the location of the ATF flow should be between the transmission external cooling loop outlet and the inlet to the stock air to ATF cooler. For that configuration the coolant to ATF cooler could drop the ATF temperature to the cool end of the radiator (150 deg. F.) and the air to ATF cooler could drop the ATF temperature further to that of ambient air plus the amount warmed by the A/C condenser. Do you know if that is the configuration for the Super Duty? I wonder if the cooler would fit in the engine compartment below the battery tray. I was potentially planning the space for an electric power steering pump and replacing the mechanical pump with a second alternator. Battery technology is rapidly evolving and I still haven't given up on the possibility of an electric motor driven supercharger for modest boost at low engine speeds.