Well good to hear that unhooking the batteries reset it for you. The fluid and filter will help out too. You might also check to see if you have a factory in-line filter that is up by the cooler for the trans. Its a round little black filter sometimes hidden by the grill of the truck. If you have one nows a good time to change it

 

PCM controls the tranny, no TCM. I've had to pull the fuse a couple time on another truck. Turned out to be a hanging shift solenoid. Glad it reset for you. Hopefully the fluid flush will solve you trouble.