[muddog321]

Check the 4wd and ATC fuse. Then you have a sensor on the front axle to tell the TCCM that the axle coupler is engaged - unscrew that and push the ball in and see if it then works. Remove the battery cable for 30 min and see if the TCCM reboots. Last is the encoder motor that moves the arm for the vac switch on the case and engages the front drive shaft.