Got into truck this morning , when I got on highway , I noticed that it did not shift into high gear or lockup , I do have a added lock up switch , no response to switching .
Pulled over at coffee shop , checked fluid , looks good [ color & level ] .
I was thinking , possibly the governor ?
So shooting for ideas .
Thanks

 

Got back in truck & drove , its working again , which reminds me , I have had some other rare issues , like the warning lites not going off after running , so what I have found is that after either high millage or hanging to much off ignition key [ wearing out the lock/switch ] , that when this happens , the electrical connection in the sw. loses contact .

 

or it could be your crank positioning sensor.
happened to me and it was very pricey, $1000 total.
i had the same symptoms and my tachometer would shoot all over the place

 

No tach issues , it is a symptom I have noticed several times with different aspects of the truck , some have been that the warning lites on dash would not got out after starting , wiggling the key would make them go out , so another dodge part outlasted by the Cummins .

 

Maybe check your grounds?
When i was having the same problems, this was the first place I was told to check...

 

I dont want to burst your bubble, but a crank positioning sensor is around a $100 and is just one bolt and a plug right on the harmonic balancer. It took me less than a half hour to change it and that was getting out the tools, installing, and cleaning tools and putting everything away.