Questions answered here:
No shutters on this one.
According to the messages, it is the engine getting hot and the computer reduces the engine power to cool it, not the transmission getting hot. (really exciting when the speed drops to 40 mph and traffic is going 65-75.
There is no reasonable access to the front of the radiator.
There appears to be a separate transmission cooler radiator under the engine's radiator.
There is a very large shield of some sort (maybe plastic) under the engine and entire surrounding area. (I suspect it's trapping lots of heat )
Found the specs on the thermostat and will try one just a little bit cooler.
Will also try removing the large shield beneath the engine.
I have fairly good access to the bottom radiator hose. I also have a heater radiator, an electric pump, and a cooling fan that fits the heater radiator. I can tap into the bottom hose for input to the pump, the pump output would go to the extra heater radiator input, and then the radiator output would go back into the bottom radiator hose about 6" further down the flow. That would add additional cooling to a portion of the coolant in the bottom radiator hose.