I have a 1997 dodge 2500 with a 360 mag in it. I went to put it in 4wd and pulled the transfer case lever and went to go but i wasnt in 4wd i had to tap on the vaccum actuator on the front axle and then it locked in. could it just need takin off and greased or something else bad? thankyou

 

the CAD is an easy item to fix/replace as long as you are getting a good vacuum to it.
Just google the CAD unit and I think they are fairly cheap and easy to replace.

You migh even be able to tear it apart and clean it.