tried a search but could not find any answers.

The wife and I were traveling south on the Interstate and saw a Chevy in the median that had spun out in the rain. Pulled off the side of the "I" and backed up. Well due to the rain and wet grass I started to slide down into the ditch. Stopped the truck and tried to put it into 4x4. Well the truck would not switch into 4x4. Tried several times. The 4x4 light would not come on nor would I hear the "Clunk" when switching into 4x4. I have an 05 xlt 5.4l with electronic switch 4x4 with 50k miles. Last time I had it in 4x4 was a couple of months ago. I will put it in 4x4 every couple of months while off concrete every couple of months.

Anyone have this problem before, and if so, what was the outcome. Thanks in advance.

 

where you tryin for 4 low or hi .. if low .. you need to be in N... for hi.. you might have blown on of the auto lock hubs .. iv gone thru 2 already .. if it makes a grindning sound thats a deffinite

 

Possible a faulty vacuum solenoid for the IWE hubs the solenoid is on the firewall near the battery