P0743 on 98 Windstar

I have a 98 Windstar that displays P0743. It will show up in pending and will occasionally turn on the serice engine light. I can clear it, but it eventually will come back in pending for a couple of miles, and then will set the light. No other codes are present. I have replaced the wire from the PCM to the connector on the trans (several other discussions talked about worn wires). The van seems to run ok and shift fine otherwise, but still pops up the code.

I have also added Lucas Trans additive, thinking maybe it will help to loosen up the solenoid (if it is a stuck solenoid).

I also tried running it with no overdrive thinking I could keep it from attempting to use that part of the circuit, but it still displayed P0743.

The van was sitting for about 3 years and it had a bad trans. I replaced the trans with one from a junkyard. That van had been recently running until the engine broke, so the trans had recently been run, and did not have any codes.

Does anyone have any other suggestions in addition to replacing the TCC? I am not sure where it is located, but I suspect it is behind the side pan. I was also thinking about trying to cycle the solenoid by just applying power directly at the transmission side of the connector, but not sure if it is driven with 12 volts.

Thanks for any suggestions.