Hello everyone and thanks in advance for any help or advice you guys can give me!

I'm experiencing the same problem a lot have with the ESOF not engaging. When I shift into 4wd hi or low I can hear the transfer case motor moving into what I believe is the correct position. I've shifted into said drives per the manufacture spec way to do it, as well as in drive while moving forward for 4wd hi, and in neutral with foot on the brake for 4wd low( even tried slowly rolling in neutral with foot on break in hopes of it engaging it). I've manually locked the hubs because I do have some sort of vacuum leak( I know this because while in 4wd hi after a short time the defrost gremlin comes and steals the air out of the vents and redirects to the defrost). Also, when I shift into either drive hi or low the correct light illuminates solid.

If I lock the hubs the vacuum leak doesn't effect the 4wd in another way correct?

Can with the hubs locked can they still fail and not engage( they both move freely and there is no binding)?

Is there something that would cause the 4wd not to engage that I'm not thinking with the transfer case motor moving and appearing to engage?

Thanks again in advance!

 

If you lock the hubs (righty tighty) and the t-case engages is will work unless something is broken in the hubs or diff. Your last 3 sentences are a bit jumbled up.

 

EX I appreciate you pointing out my few sentences that were a little miss worded and helping with the problems I'm actually having.

I meant to say,,, If I lock the hubs, the vacuum leak doesn't effect the 4wd in another way is that correct?

With the hubs locked, can it still fail and not engage( they both move freely and there is no binding)? Meaning with the hubs locked what would cause them not to work if they are locked in place.

Is there something that would cause the 4wd not to engage that I'm not thinking, with the transfer case motor moving and appearing to engage?

 

You might try making sure the transfer case is in 4 wheel by jacking up all 4 wheels at once and watching to see if the driveshafts turn. If the front driveshaft is turning and the front wheels aren't that means there must be something in the front axle that isn't doing what it's supposed to do. Most likely the hubs.
You should switch the transfer case into 2wd to see if the front driveshaft stops turning. There might just be a little drag turning the front driveshaft in 4wd so if it stops turning in 2wd then it's not drag turning it.
The only thing the vacuum is attached to is the hubs.
If the front driveshaft turns, look at the u joints in the knuckle. The ones at the end of each axle shaft. (could be only one turning if you don't have limited slip diff) If they're turning then it's a hub lock problem. (check both)
Good Luck.

 

Thanks Dave! Ill give your suggestion a try. I did a little research and thought the front end on the Excursions was a open front diff. From what I understood only a few would be limited slip front end bc it would cause driving issues.

 

That sounds about right. Well if only one axle joint spins then you should be able to stick a screwdriver or something into the joint (after it stops) to keep it from spinning and the other one should spin.

 

So I decided to verify that the hubs were free in auto, and verify they would lock in the lock position by turning the U joints on each end of the axle. Driver side did exactly what it was supposed to and would catch and lock in the lock position. However when I went to the passenger side the axle was free spinning in the lock position. I took the hub out and to my amazement there were plastic chunks in the hub cavity!! The plastic cover that holds the guts of the auto hub had broken into a dozen pieces. Now will be looking into locking hubs.

 

Thanks for letting us know. Glad you found it. Hope that's all that's wrong.

 

Lots of stock ones out there....................save your money.

 

first time reply, not sure if this is where it should be but can't figure out where to start a new post? I'm not getting power to my shift on the fly switch but all the fuses i can find are fine, does anyone know which of the four wires are supposed to be hot that go to the switch and if so where does the wire go? does it go to the back of the fuse box under the steering wheel (2002 f350) or does it go some where else? I would think it would go to the fuse box but before I take it off to test it's continuity I'd like to have some idea, thanks.
David

 

post 116 has this quote. It could be that you don't have power at the switch because of the time out of the GEM module.
I would need a factory manual for your wiring diagram to find where the wire goes but my guess is the GEM.

 

So does the power normally go from the battery to the GEM to the switch then relays and transfer case? I haven't found any good diagrams yet.

 

Sorry. I'm not sure. I know the GEM is in it somewhere. I had a bad connection at its plug and that fixed mine. I could look at my manual but it's for a 2004 and might just confuse you. The GEM location is different in many of these trucks. Mine is behind the glove box.

 

Thank you, I will check the connections behind the glove box. I believe the GEM is there but I have two similar boxes, not sure which one but have a good idea, checking connections shouldn't hurt. I have heard of the GEM being the problem but wasn't sure what the symptoms were.

 

Just a suggestion that could shed some light. While you're looking at the GEM plug compare the wire colors to what you see on the back of the switch if you still have the back of the switch exposed. Might tell you something.