transmission issues
 

Have a 2001 2500 5.9 with an automatic.

Seems to shutter between shifting gears especially 1st and second. Also when it is first starting out or cold it will fall into neutral and have to rev it up and hold it there then it will pop into gear. Also overdrive seems not to work. Or at lease the light doesn't work when the button is pushed and seems there is no change.

Just did a service on it with a new pressure sensor and the other plug in the pan.

Any thoughts?

You should let the engine run with the shifter in neutral for at least 30 seconds if the truck had been parked for a longer time.
This should get rid of your cold problem.

The 1-2 problem sounds like you need to check your front band adjustment.
The OD off light and button are a bit harder. It might just be the button or the wiring that is having problems.

Ill let my dodge run idle for a few sigarettes,,, 10 to 20 minutes at neutral, that the oil gets allover the gearbox. Tho i have a competition trans, not the groend one.

I adjusted my bands and added some additive to oil and it works a lot better now.