95 Dodge diesel will not go into overdrive or lockup. Check with scanner for codes found nothing. When put in drive with scanner on it shows that it is in park or neutral. Truck shifts through all gears but overdrive and lockup. As soon as it shows the pickup is in drive on the scanner it shifts fine. This has been an intermittent problem but has gotten worse. If anybody has dealt with this before ideas would be greatly appreciated.

 

If the PCM still thinks the truck is in park or neutral, it isn't going to engage TCC, or O/D. Might be as simple as a bad switch.

 

Thanks for getting back to me. Is this sensed from the neutral start switch or another switch, and can you tell me the wire number or color code going from the transmission to the pcu ?

Thanks

 

Yeah, park neutral switch as same one as for the starting circuit. You can download a service manual for your truck from here. Wiring diagrams are in section 8W.

 

Thanks for your help, I’ll let you know what I find out .

 

It could also be throttle sensor that is stopping from lock up and 4th gear. I've had TPS show to wide open throttle or 100% according to PCM. And the torque converter wouldn't go into lock up.