I have a 2005 lariat f-150 4x4 supercrew, I just started to have a problem with my 4x4. I hear a fairly loud grinding sound coming from the front drivers side when I put it into 4x4 it stops the take it back out its gone. If I drive 15 miles +/- it may happen one to three times or not at all, it has happened at any speed from 5 to 60 mph. I have 38000 miles so just out of warrenty, I would like to fix it with out going to the dealer and spending a lot of money. or do you think I could still get it covered? Thanks

 

Sounds like the hubs are not engaging I just had mine in 2 weeks ago I did not have any grinding It just would not engage It turned out to be a broken rod in the transfer case I only had 13xxx miles on the truck My 3-36000 warrenty was gone but i bought a ford esp before the 3-36000 expired Total bill was $709.xx I paid $100.00 and drove off Your problem sounds alot like a bad vac leak The hubs are not engaging Good luck

 

Sounds like a bad IWE or vacuum leak to it. Default position for the IWE is locked, that is why the grinding when not in 4wd and no grinding when locked in. It will have to be diagnosed and fixed and or replaced.

 

my 04 fx4 had the same thing twice,ford put a new vac valve on the firewall behind the battery.Also you may need to cover it with something because it is right were the front cowl dumps the water off of the windshield allowind the water to drain right on it.hope this can help!

 

Make sure that you get the revised IWE solnoid for the firewall it will come mounted on a new bracket the new bracket has a Rain hat design. Also check for vaccum leaks some seem to melt near the pass side exaust manifold.