Have a couple questions about my (driven by the wife) 2004 Expedition.
First, I have been having an issue getting it to actually engage in 4 wheel drive for a while. Of course, every time I really get to check it out, get under it, and see what is happening...it works fine.
But from time to time, intermittently, it does not kick the front end in.
Dash light always lights as it should with the switch position, but many times now it doesn't really engage the front end.
Yesterday as I went to drive up my steep snow/ice covered driveway (Michigan-blizzards are us lately), it became obvious that even though switch and dash light showed 4 hi, it was only rear wheels turning.
So this morning I pull it onto the snowy drive, switch back and forth, forward, neutral, reverse... try to do everything I can to let it kick in.
Rear tires spin and spin, then I do a donut in the drive with no sign of front end working.
In and out of 2 wheel, 4 wheel, and hi and low gears with the switch.
I can tell the case shifts, obviously into low for sure.
So I pull in garage, jack front tires off the ground, and start truck, put in neutral, and set dash switch to 4 low.
Drive shaft doesn't turn a bit.
Front tires off the ground and I can turn driver's side forward, passenger's turns reverse and vise versa.
Seems like it is locked in 4 wheel, so I pull back onto driveway and YEP front tires spin as I watch out the window.
Any know issues or troubles that come and go??
Only thing I am thinking is the electric motor on the transfer case that does the shifting...?
Are there "synchro" type components in the case that might need attention?
Appreciate any help !!!
And now question # 2...
When I was on the steep slippery drive yesterday morning, I slid backwards into the porch on the side of my house
Got the deck fixed alright.
But, the passenger's side back quarter panel window got broke/shattered.
Now I also see that the top of the rear quarter, under the window, has a couple dents and...
the panel (circled in red with arrow) is wrinkled pretty badly.
I see that there is a plastic trim piece covering rivets on the hatch/door side.
I don't think I would have any issue drilling those out and replacing with pop-rivets.
But...
does the side glass need to come out to replace this piece?
Any idea what it is called or a part #?
I been searching rear trim, window, black, quarter, exterior, filler, and everything and anything else I can think of this might be named, called, or described as...
Again, appreciate any help, advice or direction to head.
THANKS ! ! !

 

Window molding, right.
FORD Expedition Parts

 

Thanks for that !!!
Appreciate it
I had new glass put in yesterday.
I am hoping that it doesn't need to come back out in order to put replace the molding.
I been thinking more about the 4 wheel drive actuating too...
The firewall mounted vacuum control seems like it could allow my situation if it does not cut off the vacuum when the switch is set to 4 wd.
Wondering if shutting the truck off and moving restarting with switch already in 4wd is what has been allowing it to finally engage...?
Firewall mounted "actuator" won't cut off the vacuum once it is a plied and engine is running, but is able to block it when engine is off? ? ?
I am wondering...

 

I also see little vacuum checking switches...
Looks like check valves.
I do not have any dis-engage issues (I think) but wondering if one of these check valves filing would keep it from engaging...

 

Not really, the vacuum only engages the front axle or hubs. In your case you said the front drive shaft didn't turn which makes it a transfer case or electrical issue.

 

Oops, sorry.
When I said that it did not turn, I was trying to say that when I grab it and try to turn it by hand, it is locked solid.
Seemed like it was engaged at the transfer case end.
The hubs seemed like they were each engaged too when I was under the truck.
They were not "free wheeling" anyways.
That is where I would turn driver's side CW and the passengers would go CCW.

 

I had issues with my 4wd taking forever to engage and then not wanting to come out once it was. This is right when I got it before I did any fluids. When I did the transfer case fluid it was basically laquer coming out of there. 3 quarts of fresh ATF and its worked fine since. Could be as simple as a fluid issue? I'd do a drain and fill on the T case if you have not in a good while.

 

I will check the fluid level in the transfer case. Appreciate that.
It has been a while since I checked it.
The wife drove for a while yesterday on our still icy, slippery, snowy roads and says that even after I had 4 wd engaged at home, it felt like it slipped out and disengaged right while she was driving. She had stopped, flipped the selector switch and had it back in. But by the time she made it home 2 wd again. I can only imagine that somehow vacuum is incorrectly getting sent to the hubs even with the dash switch in 4 wd...

 

Oh, and bad news for me
Wife had taken a picture of the broken back window.
I can see the front edge of the rear window molding that got dented up and it is under the edge of the rear quarter glass.
I can see rivets holding that edge on too.
I had the glass replaced right away so we could drive the truck.
I had hoped to be able to replace that molding, but looks like glass has to come back out in order to get at it's rivets

 

Thinking I will head o while, maybe take my son so he can at least flip he switch around on the dash and see what the vacuum stuff does.
And check my trans case fluid

Still thinking about the rear filler molding panel too...
Maybe when it get warmer I will see if the interior plastic lets me get to the rivets from inside...?
Thinking maybe I could grind or drill off the inside of them and re-install new ones from inside out...
No idea, but gives me a hope and a dream

 

Well that changes everything. I suggest first to get all 4 wheels off the ground and put it in gear. Then find a safe way to see if the front drive shaft is turning. If it is then your t-case is fine and the problem is with the front axle hub lock in system. That would make the repair much easier and less expensive. And yes, now it can be a loss of vacuum issue.

 

Spent an hour checking everything I could yesterday and no idea why it doesn't work SOMETIMES.
Checked the transfer case fluid; full, clean, and looking good.
Had my son flipping the switch and could not get anything to not do what it is supposed to.
Underneath I can hear and feel the electric motor switching the case like it should.
Drive shaft spins free in 2wd.
Locks up at the case quickly when switched to 4wd with the front end off the ground.
Pulled the wires and vacuum line off the firewall mounted solenoid.
That seems to do exactly what it needs to.
When hooked back up, hubs lock, engage, and disengage quick like they should too.
Set truck on the ground pulled onto snowy driveway and it spins/doesn't spin just as it should depending on where it switch it to.
?????
Of course, when I am able to check things it works great.
I may replace that vacuum solenoid since it is inexpensive and easy to do.
Other than that I am pretty lost and do not know what to do until it screws up again.

 

Read some of the thread below.
The mention of needing to vent the vacuum has me wondering if that is what happens to my Expedition.
If something were to clog the vent line I could see the hubs not being able to engage.
I did not realize that there was a separate vent line.
Thought once vacuum was no longer being applied the hubs would just engage.
I think I will take a closer look at the small vent tubes.
It also mentions the check valves and vacuum reservoir.
When I first saw the reservoir on the schematics, I wondered if I had an issue.
I was thinking with the check valves and "storage" of vacuum, it should keep the hubs disengaged when parked with motor off.
Read a little more and see how that is just during full or high throttle driving.
So I still have not seen anything that does not seem to be doing it's job.
Just going to check the vents soon.

HOW TO: Diagnose your 4x4 system. ESOF - Ford F150 Forum - Community of Ford Truck Fans

 

What spins, both the front and rear or just the rear?

 

Sorry.
I am just not being very clear in what I am writing here.
If I set switch to 4wd both front and rear spin in the snow like you would want and hope that they would.
Set the switch to 2wd and only the rear spins.
I just cannot get it to screw up any more.

I have replaced both the front hubs on the truck.
Some things I look at make me think that the IWEs are part of the hub assemblies and others look like separate components.
???
Wondering if the IWEs are original now, or if they are brand new when I put new hubs on.
???

Also, the wife keeps making a point that even if 4wd engages when she is parked and first flips the switch to 4wd, later it feels to her like it slips out and dis-engages while driving.
Knowing that it takes the vacuum to pull into 2wd, and not the other way around, I just would not think that would be something that would happen. But I am now wondering, what the heck is going on. Are these things OK in the driveway and letting loose going down the road, at speed, or under torque...?

THANKS for the help again !!!