Will a transfer case from a 98 or 99 dodge ram fit in a 2001 dodge ram?

Yes it will I had many people tell me no it won't but I have a 99 transmission and transfer case in my 01 dodge and everything worked fine

I pulled a transfer case out of a 1997 and there's some kind of sensor I can plug in but I don't have that on my 2001 transfer case will it work?

you swap that sensor with the vacuum operated sensor.. I am trying to buy a dodge ram transfer case to fit my dodge Durango both 98 same transfer case Np231d from the looks all i have to change is the front axle yoke and the sensor from vacuum operated to electric.