I would get under the truck and check to make sure the transfer case gear selector arm is adjusted properly. It can easily slip.
The easiest way to be sure if you are in 4wd is to make a sharp turn in a parking lot and see if the fron wheels skip. If they don't, you're not locked in 4wd.
My 2000 R/T transfer case makes a very audible clunk when shifting into and out of 4wd lock.
I believe the manual actually reccomends that the vehicle be moving very slowly when you shift into or out of 4wd.
Hope this helps.
The easiest way to be sure if you are in 4wd is to make a sharp turn in a parking lot and see if the fron wheels skip. If they don't, you're not locked in 4wd.
My 2000 R/T transfer case makes a very audible clunk when shifting into and out of 4wd lock.
I believe the manual actually reccomends that the vehicle be moving very slowly when you shift into or out of 4wd.
Hope this helps.