Shift Ranged Inhibited

I've had quite a few "shift range inhibited" faults with no check engine light lately preventing me from going into reverse. Cycling the key switch a few times usually allowed a reverse shift. I replaced the NSBU gear selector and thought that cured the problem, but two days later the fault came back with a check engine light, and this time there was no clearing it. I rolled the truck down the driveway and headed to my local dealership in all forward gears. The fault code was a PO743 and the torque converter clutch solenoid was replaced and I've been good for over a month now. $336.00 out the door. The tech told me that on this particular transmission that reverse gear is controlled by the afore mentioned solenoid.

Thanks for the info. I would have guessed an NSBU, but apparently there are other possibilities.