I have the same problem and a theory about what it might be, not confirmed yet; mine only does it when cold or when it sits for several days, also after driving for about 5 minutes it goes away. Once it warms up for the day it works fine even if it sits all day and I use it that evening. After several wiring and parts checks, I decided to tap/pull and reinstall the transmission control relay several times in the mornings before starting the truck, so far so good. I've been doing it for three very cold days. I'll now swap relays with the wipers (same Mopar part number) and report my findings. A review of the diagram makes sense as I believe not energizing the relay is part of the ECM's strategy to activate "limp mode". Under score "believe", maybe someone can help on this. Either way not energizing the relay kills the transmission governor, converter clutch and overdrive solenoids.