Have a 2005 Ram 1500 2WD with appox. 82000 miles on the truck.
Have had ZERO issues with the Transmission, I service it every year in the spring.
I drove home Christmas Eve park the truck - got in the truck the next morning started the truck put it in gear & Nothing Happens.
RPM's do not change, no hint of the truck going in gear.

I have rocked the truck - revved the engine - Zip, Zero Nothing Happens.
Transmission fluid is nice and Red, not burnt and as I said I have had no issues at all with the truck/transmission.

Any Suggestions

 

Maybe your trans control module, shifter wire or wire running to the arm, or threw a gear. I had a torque converter jump a plate once that wouldn't let it go anywhere.