I have an '03, 7.3 Lariat F350. When I turn the dash switch for 4x4, my 4x4 light comes on, but my truck will not go into 4x4. If I get out and lock in the hubs, I then have 4x4. My truck has about 76000 miles. Any help will be appreciated. Jonathan

 

Jonathan,
Chances are u need to replace a couple of inexpensive yellow O rings in your front hub assemblies. Here's a LINK on how to do it. The link is actually for needle bearing servicing
but goes over replacing the O rings that are the main culprit.
Also, check out this thread on hose seal at the hubs: LINK
Nut

 

PSNut, Thanks for the info. I went down to the local shop, but the were not able to help me. So now I have an appointment with the dealer. Hopefully, I can get away from there with a little coin still in my pocket. Later, Jonathan

 

Jonathan, You may want to vacuum test your front hubs first to see if they are leaking. Problem could also be the vacuum pump, the solenoid that directs vacuum to the hubs, broken/leaking vac hoses. If hubs hold vacuum, your orings should be ok.

 

Or you may just want to pitch those ESOF assemblies in the can and go manual and be done with it. That ESOF **** makes a good spot for a gauge or chip switch.

 

Tenn, Still need the ESOF **** to engage the TC and low range. Unless there something out there that does away with the electric shift motors.

 

My bad, humblest apologies.

 

Jonathan, I had the same problem last fall. Tracked it down to the transfer case shift motor. I took it off and it smelled burnt so I replaced it and it fixed the problem. Dont know if it will fix yours but its an idea. Good luck