2007, 5.9, 48RE, Not going into OD

[DaveAlex]

2007, 5.9,48RE.  I am trying to help my son with his transmission problems but have run into a brick wall.  He originally just had poor shifting (shuttling). He changed the Transducer and upgraded to a BW solenoid and fresh fluid. Transmission worked like new. A short time later, at the end of a 600klm trip, he lost 4th (OD) and lock-up. He limped it home. He also had intermittent ABS and Brake Lights that changed each time he drove it. He took it to the dealer and they diagnosed that his Power Module (TIPM) had failed due to corroded pins. They replaced it and all the lights and codes were gone and the truck seemed to be fine, however once out on the highway it would not go into OD (2000 RPM, 50mph/80klm). Lockup is fine in all gears. He then replaced the OD solenoid and still no shift. We have removed all of the connectors, inspected all the wires and pins and everything looks like new. Transmission has 175klms (100k miles) and has not been abused in any way. Not sure what to chase next? Any help would be appreciated. Dave