First off, whatever happened to manual hubs? i liked those much more then these new IWEs.

Ok, i've done alot of reading on the 4wd system of these trucks. My buddy's '05 fx4. has only 86k miles on it and the 4wd is giving him all kinds of problems. transfer case i believe to be working properly i can hear it engage when 4wd is selected. We were told by the dealership he had a bad passenger side front wheel bearing, so we replaced that. Still was getting noise for the frt end. Now being in Michgan in January it would be nice to have 4wd and the frt passenger hub will not engage. I did some quick diagnostic work on it and could feel the vacuum solenoid clicking when 4wd was selected on the dash. so i dont think that has shorted out.

but the hub will not engage. so im thinking that the hub got wrecked.

if i pull the vacuum lines off the IWE shouldnt the hub engage if the hub is still intact and working correctly? ruling that out as a possiblity.

to do test the vacuum system how would i do that? i have access to a vacuum pump and gauge. when 4wd is selected, no vacuum should reach the hub, im i correct in thinking that? but if for some reason the vacuum cannot be released wouldnt that cause the hub to not engage?

Im at a lost and need some help.

Thanks in advance for any advice

 

One of the best diagnostic write ups I have found to date.

https://www.ford-trucks.com/forums/8...then-some.html

 

You are right in your thinking. But if you have already read the post that Sako 75 pointed you to then you know that.

 

You could have a sticking 4x4 solenoid(the solenoid on the passenger firewall). Your IWE's should hold a vacuum. If you jack the front wheels up, and disconnect the hoses, the Iwe's should lock when vacuum reaches about 8 in hg. They will then unlock(free spin from the axle) when the vacuum gets down to a bout 5 in. hg. If they do this, the IWE is working. You either have a sticking 4x4 solenoid, plugged vacuum line to the IWE or a bad IWE/Hub assembly. The IWE could be stuck or stripped...

 

well i new development is the truck will work in 4lo. The frt passenger wheel gets powers in 4lo. but in 4hi it will not lock just makes a ratcheting noise. any ideas

 

Well it doesn't matter wether you are in 4hi or 4lo. The 4x4 solenoid is an ON/OFF solenoid. check for the iwe's to hold vacuum. then check the smaller of the 2 lines for blockage(ice or dirt stuck in the end of the line up near the frame).

My money is on a stripped/leaking IWE that ground down your wheel bearing/hub gears...

 

My 05 SCREW is currently at the dealership getting a new front differential. A lot can be learned from getting the front wheels off the ground then turning (spinning) the tires manually. Also if it is the IWE actuators you can easily do it yourself. Im not much of a mechanic and did one side in about an hour.

 

The thread posted earlier is good for trouble shooting. Here's one that helps with the replacement of the IWE[s]. ...has pictures too.

http://www.f150online.com/forums/2004-2008-f-150/360269-iwes-removal-replacing.html

Reading through both threads you'll see me working through the same issue. With success. And I'm no steller mechanic.