Good after noon..... my dads truck wont shift in to overdrive.... now we already had it rebuilt new solenoids, and we bought a refurbished computer ECM.....still same thing.......so we sent his old computer off to have it tested ... it just came back as GOOD!!!! any idea what could be the problem.. i have heard grounding and or the wiring harness on the transmission thanks

 

Is it setting any codes? Does the trans temp light in the dash come on? What happens when you press the O/D off switch?