Always in AWD

It will not turn because the no vacuum engine condition engages the front IWE actuators which locks out motion I think, correct? I will double check and confirm when I get home tonight. Thanks for the quick response.

Cannot turn front drive shaft in either direction, but there is about 10-15 degrees rotational play.

Yes.

I thought that when the car is off there is no vacuum going to the IWE solenoid and therefore the actuators are engaged with the axles by default when the car is off correct? Not trying to argue but wouldn't the CV axles and thus the front driveshaft be in a locked position any time the vehicle is turned off or am I mistaken?

With the front wheels off the ground in the car in park with the emergency brake on when I spin the front wheels the axles differential and driveshaft all turn as a rotate either tire. Not until I turn the vehicle on does the vacuum solenoid retract the I WE actuators in the front wheels spin freely. When I rotate the shift selector to all wheel drive I feel nothing in the transfer case shift motor when I turn the shift selector to four high the motor actuates and 4 High Wheel Dr. Locks in. When I turn it to four allow the shift motor actuates and the car locks into four-wheel-drive low. As I go backwards to four high the shift motor reengage is for high and when I go to all wheel drive the shift motor goes to the two high position and when I select back to too high the shift motor does nothing and I don’t hear any activity when I go from all wheel drive to two high. With the car into high and me backing down the driveway the front driveshaft differential and axles are rotating even though the front wheels are not engaged. I am wondering if the electron ask that tell the Transfer case to come out of all wheel drive is either not making the decision to do so or is doing so and that signal is not getting to the transfer case or it’s getting there and it’s not actuating to tell the transfer case to be into high versus all wheel drive.

The 2003-2005 expedition reintroduced the 2high feature that sent all torque to the rear wheels only to take advantage of the gas mileage saving feature when the car was only in 2 high (I have read this in many places including my owners manual). I have 2 friends where I work with 2004's. When they are in 2H, none of there front drive mechanisms are engaged, and it can be seen that the cv axles are not turning when the car is slowing rolling in forward or reverse when the selector switch is in 2H(my car is always engaged). Not until A4WD is selected does their front drive gear engage and is available for 4WD should it be called upon to engage. Mine used to be AOK for years and not until the past 12 months have I noticed the additional vibration and "drag" on the rolling of the vehicle. My guess is that 4AWD is the default condition when the vehicle is not running. When I start it, the transfer case should receive the signal to disengage 4AWD and only transfer torque to the rear wheels if the selector switch is in 2WD. If I knew the relay or relays that transmit the info I might be able to replace to resolve.

https://en.wikipedia.org/wiki/ControlTrac

This is one resource is found describing my vehicle. You'll find the sentence I referenced.

Two High mode was reintroduced on the redesigned second generation Expedition (U222) for the 2003 model year and featured a new full front axle disconnect system with vacuum operated front locking hubs that would disconnect the front axle, front differential, and front drive shaft when not needed for quieter, more fuel-efficient operation on pavement.[7] Ford claimed that the improved Two High mode could help increase fuel economy up to half-a-mile per gallon of gasoline.[7] In Two High mode, torque is routed to the rear drive wheels only, imitating rear-wheel drive.

Expedition also offers a new dedicated two-wheel-drive mode that completely disconnects the front axles, differential, and driveshaft when not needed for quieter, more fuel-efficient operation on pavement †saving up to a half-a-mile per gallon of gasoline.
I really do appreciate your help. Just trying to keep my main support, you, on the same page with me to resolve this issue.
Wish I had a list of relays that impact this system. I would change them all out and see. I have used the owners manual basic stuff and checked all they suggested that had anything to do with 4WD to no avail. Gonna go back to the shop manual tonight and see if I can get lucky.

Jim

Hi Roy,

Any update.
Here are some additional thoughts if we work it backwards. I have been doing a lot of reading and can't find the answer to how this happens. Let us say nothing is wrong with a new 2004 Expedition and shift select from 2H to A4WD. What is the electronic pathway that occurs to get the front driveshaft to turn full time. If we knew this we could probably trace the potential path backwards and discover the culprit.

Another thought. If the transfer case shift motor has on three positions 4H, 4L, and 2H which is true. And it stays in the 2H position for 4AWD. Then the only thing that can trigger a change in the transfer case to engage the A4WD is through the one large white wire entering the transfer case that I believe activate a magnetic clutch (I think).

So if the default position of the car electronics and mechanics when off is A4WD. Which I am almost positive it is. Then I start the car. Shouldn't the white wire receive a signal to move something in the transfer case to throw all power to the rear wheels? Kinda like the IWE actuators. They are always engaged when the car is off. Then you start the car and the vacuum through the solenoid disengage them and holds them in that position until the solenoid engages them or you turn the car off.

Jim

Exact same Part. The other acted the exact same way as well. Oh, and I removed the white wire properly from the harness that feeds the clutch coil pack thing in the transfer case and it had zero effect. Interesting huh. I am leaning in the direction that the power is not getting to that wire to trigger activating the clutch which probably holds the transfer case in 2H mode but not sure what relay that could be bad is on that voltage pathway to that white wire. I will check again but have not seen a code thrown ever. Wonder if I jumper wire 12 volts to that coil clutch pack whatever and drive it down the driveway? What do you think? I'm still searching.