4x4 Troubleshooting Question

[AZHellfish]

2009 Ford Expedition 4x4 SSV.

I just bought this vehicle to set up for camping. It was a police supervisor's truck and its in generally excellent condition.

The 4x4 system is not working properly.

With the front wheel elevated on jackstands:

Engine off, 2WD Selected:

Both front wheels will rotate by hand. In the forward rotation they "click," like the splines are barely touching. but not engaging. The front axles don't turn, rotating the wheels forward. If you hand rotate the wheels in the backwards direction, the splines do engage enough that the axles turn with the wheels.

Engine on is the same.

If I select 4A, 4HI or 4LO, nothing happens, the wheels click the same. The green 4X4 light on the instrument cluster does not light up.

If you get under the truck and hand rotate the front drive shaft, the front axles do turn, running or not, 2HI, 4A,4HI, 4LO selected, makes no difference.

I checked all the fuses that the manual lists as having anything to do with 4x4.

I replaced the IWE Solenoid (by the battery) didn't help.

I pulled the line of the vacuum reservoir, I did get a little pop like there is vacuum there.

If you pull the vacuum line off the hubs, I did not notice any vacuum noise.

I tried tapping on the TCM to see if it might be stuck.


Any ideas?

 

[ExpeditionAndy]

Welcome to the Forum AZ.

I guess the first place to start is to read the code to see if there are any and then go from there. When in 2WD the wheels should spin and the axles shouldn't turn In any other mode the hubs should lock in and the axles will turn. This video might give you some insight.

 

[Bedrck47]

Read the attached

https://www.ford-trucks.com/forums/...the-iwe-system-and-then-some.html#post7322441

 

[AZHellfish]

From what I'm learning the "clicking" at the wheel is usually caused when the locking hub gets damaged by water or some other cause of "partial vacuum." Maybe a leak?

However, I still have the 4x4 switch issue. No 4x4 activation. If I bypass the solenoid (by direct connecting the vacuum line as shown in the video), the hubs do retract and free wheel, but there is always 12v at the plug at the solenoid, no matter the 4x4 switch position (4Hi, 4A, 4HI or 4Lo). But... disconnecting the plug from the solenoid does not help either.

Summary:

If you connect the vacuum supply directly to the output line of the solenoid, the wheels will freewheel and not click.

The 4x4 switch doesnt change the voltage at the solenoid, its always 12V.