When I got the truck, the 4x4 didn't work. I replaced the switch, the actuator, and checked the wiring.

Since then the 4x4 had been working, but whenever I engaged it while in drive it made a short, loud grinding sound, but it worked alright until I went to disengage it, and it made the same sound.

Semi-recently it started to shift into 4x4, same as it was. Then when I went to disengage it, the 2wd light will flash for a minute before the service 4x4 message came across the dash. If I did the transfer case reset procedure, it would go back to 2wd until the next time I changed it back.

Now the 4x4 won't engage at all. It says it is working, but the rear tires still just spin. No action at all in front.