Durango overheating question.

id let the truck cool down then start it up with the rad cap off watching the fluid. build it up to operating temp and see if the fluid starts to flow (thermostat opens) it should flow like a river if not possible water pump or some gunk build up. while it is running you can also see if the fans are kicking on. your water pump could have cavitation in it or the blades might be eroded lacking poor circulation