Without any previous trans symptoms, the truck, in the morning wouldn't change out of 1st gear, had codes 81, 2-3 solenoid circuit, and 84, throttle pedal circuit. Problem cured after days of internet searching, testing voltage at trans plug, solenoid activation, input speed sensor, changed the throttle assembly, still code 84. Codes 81,82,83,84, now occurred without starting the engine, cleared, then 84 wasn't there. Swapped in the computer (ECM) from the other vehicle and no codes. Plugged the original one back in, no codes, went for a drive, got the gears back. Most of the time was spent searching the internet for similar problems, which got me to change the ECM, and also plug the old one back in. Hope this helps other people, no money spent. That is why I choose to have two identical vehicles.