I don't know, I haven't driven in any deep water so my best guess is that maybe some moisture got into the lines somewhere. Maybe when we had the freezing rain, some water ran down the hood and into the old solenoid somehow. I don't have a clue.
But when I went to engage 4x4 the other day at the farm, it seemed like at least one of the hubs was really slow to engage. I stopped on a hill, flipped the switch, waited for a few seconds and started moving. Once on the snow it was like one of the front tires stopped pulling (or wasn't pulling) for a split second, made a good bang and started pulling again.
I'm not sure if I have a bad IWE or what the deal is. Like I said it works fine in the garage but....

 

Gah! Nevermind, we got a light dusting of snow (less than 1/2") and they salted a bunch more, no snow sitting on the pavement. Damn fools.

 

I would imagine that you could blow the lines with compresssed air to get the moisture out. Also I'd try just unhooking the lines from the hubs all together. See if you have better success with the 4wd. Try to cap off the lines though when u do it.

 

Yeah, I do want to unhook the lines and try it out. I need to get something to plug them with though.

 

Any auto parts store sells vacuum plugs/caps. This would at least confirm if it's the hubs themselves or vacuum system.