My hubs will not unlock in 2wd (engine running). The half shafts spin and I cannot spin them by hand. It is not a vacuum problem because I have vacuum at each wheel. It is not the solenoid because I bypassed it with a straight vacuum line and still does not disengage the hubs. WHAT IS WRONG WITH MY HUBS????!!!!!!!!??????!!!!!!

 

Could be the IWEs are both bad. They have seals and springs inside them that can fail when contaminated. That's why I cringe when I see all the pictures of submeged trucks... Not much in the drive train is going to end up happy after being under water.

 

If the hub has vacuum then it has to be something internal in the hub itself.

 

308, This thread explains how to replace the IWEs and also has some good pictures including diagrams that show how they work (and what could be broken). The work isn't hard to do yourself. IWEs can be bought online for about $80 apiece. They are a "Ford only" part though.

IWE's: Removal & Replacing - F150online Forums