Howdy i gots questions bout my badboy...hes an 2003 Dodge dually 3500 5.9 cummins with automatic transmission..
MY PROBLEM:
When Im driving and hit 55 mph or higher my truck like downshifts and the RPM goes up hits bout 2 and the truck will shift back up again and continue driving just fine....then again down the road when i hit 70 75 it will do the same...slow down...downshift RPM goes up....then will shift back up and continue driving just fine.
Please your answers or input is greatly appreciated as this is driving me --->

 

my old ford use to do this, they said it was some kind of sensor. that may be your problem

 

I'm going out on a limb here, but it sounds like a failing APPS...symptoms are very similar to that of a 2nd gen auto. I don't know the 3rd gen autos at all, not sure what is similar if anything.

 

maybe the MAP sensor..manifold absolute pressure sensor?

 

does it have a tps

 

TPS umm not sure....what is that?

 

throttle position sensor it messes with the tranny bad when they act up

 

speed sensor check it also tps throttle position sensor

 

Gov Pressure Sensor

 

that slipped my mind! if he hooked it to a computer would it tell him?