So I kind of suspected it wasn't working before but finally took it to the dirt to try it out. When I turn the dial to 4x4 it illuminated the light on the dash but even after driving a couple hundred feet I was still only getting power to the rear. 4lo same thing but it was in the lower gear but still only power to the rear. Help?

 

Vac line or solenoid would be 2 things to start checking.

 

You can pull to the two vacuum lines off the actuator and have someone in the truck while runnin and switch it back and fourth from 4 to 2. And while they are doing that lay under with your fingers on the end of the lines and see If you can feel pull and push.