2015 Ram 1500 Speedometer stops working after app. 10 miles driving or 20 minutes idling

[Jim Flowers]

My 2015 Ram 1500, 3.0 , 4wd with 8 speed ZF transmission with 155,000 miles on it and sometimes it starts and runs and shifts fine for app. 10 to 20 miles or just idling for 15 to 20 minutes and then the speedometer goes blank and if I stop and put it in Park I cannot get it to shift and if I shut it off it will not restart until it cools down. Then sometimes it will start right up and sometimes it will not. I wait a while and it cranks up. I have taken it to three different mechanics, all with expensive scanners. The second one said he got a PNP code (ParkNeutral

 

[Jim Flowers]

The second mechanic said he got a Park, Neutral, Positiong sensor so I order one from O'Reilly's along with the special 8 speed oil and expensive oil pan with transmission filter built into it. I followed the procedures and transmission shifted good, transmission shifted good, oile temperature 188 deg. But it did the same exact thing. It would start right up but after driving it app 10 to 20 miles the Service Selector message comes on, the speedometet stops working and if I stop it will not cramk and cannot move shifter. The lights on the dash are bright and the lights on the selector switch are on. I have checked the fuses and have not fiund a bad one. I replaced the stop light brake pedal switch. This has been going on for 8 weeks and I really need some help. Hopefully someone can help me find the problem.