Was pulling a trailer with a large tractor and had switched the 01 7.3 Ex with 300k miles to 4WD with the switch on the dash.

All was fine till I tried to switch back to 2WD.

Then it sounded like I hit some rumble strips a few times and then a constant shake/rumble till I switched it back to 4WD Hi and all was fine as far as the rumble strip feel.

Also, I tried to Manual maneuver the hubs and they are unmovable, but that has always been the case since I got it at 140k miles.

I rarely use 4wd so this is a whole new arena for me.

Thank for your help and support.
Steve

 

Try taking it out of 4x4 when your sitting still foot on brake in park. I've had to do it when in low range.

 

Sounds like you need to have the system serviced.

To get it back into 2wd, try putting the switch to 2wd and back up a few feet. There is a good chance it will disengage.

 

Ben, is on the right track. Try putting it back to 2WD while backing up, and it should unspool the hubs and unlock them if they are binding. If that doesn't work, try going slowly forward 10ft, then back 10ft several times.

 

YOU WILL alway have to do this in & out of LOW, AS well as be in Neutral..

 

The hubs on my dad's Excursion do this as well. I took a punch and a rubber mallet and gave them some gentle love and they will move. This will get you out of 4HI until you can figure out why your vacuum system isn't releasing.

 

It could also be the relay that controls the 4WD mechanism. I think it is near the master cylinder. I had that issue when I could not get it out of 4x4 unless I manually took the shift motor off of the transfer case and switch it to 2WD.

 

Thank you all for your input and I will give them a try tomorrow.
Please pardon me for possibly not using the correct terms as I know very little about this 4x4 stuff.

Today before work (I am 2nd shift) I did some testing with the X up on all jack stands.

First, I took both Hubs off to inspect. Both where stuck in the UNLOCKED position. One I could switch back and forth...the other has been damaged and is out of round so it would move only a 1/4 way with great effort.

WIth both still in the unlocked position (internal ribbed gear moved freely) I reinstalled the hubs.

ESOF is set to 4HI.

With the car OFF.
Spun the driver side front tire and the joint on the passenger side spun also (opposite direction) but NOT the tire.
Spun the Passenger side front tire and no other movement.

With X all warmed up, in neutral, foot on brake, switched ESOF to 2WD.
Put it in DRIVE.
Back Wheels Spinning Nothing happening on the front end.
No adverse sounds.

Put back in neutral, foot on brake, switched ESOF to 4HI.
Put it in DRIVE
Back wheels spinning, neither front is spinning.
However, the axle/universal joint that drives the front axles was spinning.
No adverse sounds.

Removed the jack stands to see if dorking around with it changed anything.
Switched the ESOF back to 2WD and took her for a ride.
Got up to 30 mph and the rumblestrip feel and sound returned from the front of the X. I pulled over and switched ESOF back to 4HI and did not hear the sound again.

Once back to the house, checked the vacuum hose and the driver side one was in horrible condition, missing a chunk.

My first goal is to just get it back into 2WD without it making the horrible rumblestrip sound (that can't be good).

Second, to have the 4wd part work as intended. Obviously going to have to put new hose in at the minimum.

Any further testing suggestions or next steps are greatly appreciated.
I can upload pics if necessary.

Thanks,
Steve

 

For 4WD you are going to need hubs before the hose will do you any good