Ok, lets start from the beinning. A few months ago I replaced the IWE actuator behind the battery with the hood and a new IWE actuator. Everything is all good to go after that. Well s few months later we get four days good of rain and wouldn't you know it the sound is back. So I headed to ford again and bought a new IWE actuator and replaced it. While replaceing it I took the resevor behind the batter box and look at it. I noticed debre in the tube on the box. and vaccum pressure. So I cleaned out the junk from the line. So I keep running the vaccum lines and see a small 6mm inline filter. Pull off the line there and feel and hear vaccum pressure. So I place the line back on and pull the other side. No vaccum..!! Hmm ok pull it out and see rust coming out. I bang it some more it just keeps coming out. So now I have rust in a filter. Looks like this, just black and green. http://www.optionsauto.com/images/hks-vfilt.gif
So now I bypass the filter and go straight to the IWE actuator. I have vaccum coming out the IWE actuator while running. I go to the knuckles and pull the hose off there. I have vaccum there also. Half the vaccum pressure at the IWE actuator. Same on the other side. I also notice that on the pass side the vent tube as rust / stuff in it, so I clean it out.

So here I am left with a truck that grinds and makes the ice grinding noise in 2wd. In 4wd High the light comes on you hear the transfer case lock in the axle and the normal noise I always heard when doing this. But no 4wd. Take a sharp turn no jumping/skipping, just nothing out of the front wheels, like if I was in 2wd. But hey the noise is gone. Put it into 4wd Low, the light come on and have almost no power at the wheels when I give in some pedal. I'm thinking the front wheels are not engaged and I have just spinning axles. Does anyone have the online manual to tech this. And can someone please help.

 

Let me get this straight. You find debris in the line and filter and bypass the filter so that the debris can get sucked on through the line and into the actuator. There is evidence that there is rust in the knuckles. And the 4fwd does not work. Time to open some gear cases.

 

The filter is after the actuator. It goes knuckles ---> actuator ---> filter --- Truck. Kinda dumb design. I think to make sure the actuator doesn't go again is place a filter before it also.

 

It sounds to me like you may have to replace, possibly both, driver and passenger side Integrated Wheel Ends. sounds as if moisture has entered the system from the first time your IWE solenoid went bad. Try and spin your front driveshaft by hand with the engine OFF and see if either of your axle halfs move at all. In a perfect world with everything working correctly, you shouldnt be able to spin that shaft at all with the engine off.
Good Luck
Rich