OK....I've tried to do a search and can't seem to find an answer to my problem. I have a 2002 Excursion PSD 4x4. The problem I have is that it is stuck in 4WD. The light on the dash says 4x4 even though the **** on the dash says 2WD. Here is what I've done so far.

I crawled underneath and had my son turn the dash **** from 2wd to 4x4, but no sound from the transfer case motor.

I checked the fuse #111 and that looks good...

I tried the hubs on auto, which eventually disengages (bad vacuum?)but light on dash stays on, and lock which stays in 4WD even thought he dash switch is at 2WD.

I've checked the connections to the transfer case motor and they are snug.

The streets are slick as snot so I know when it is in 4x4 or 2WD.

Has anyone had a problem with the shift range selector on the dash before?

 

Sounds to me that the transfer case motor has gone south for the winter. If you turn the switch from 4Hi to 2Hi and do not hear the motor, then it is the motor. Especially since you already checked the fuse.

Here is a TEST: Turn the switch from 2Hi or 4Hi to the 4Low setting. See if the transfer case shifts to the "LOW" setting. If not, then the motor is bad.

Lucky for you that your ESOF hubs are not working properly too. That way the transfer case which is still engaged will not do any damage to your EX will driving on dry surfaces where 4x4 is not needed. If 4x4 is really needed, then just put the hubs in the "LOCK" position and you will have 4x4.

YES...it could be bad vacuum to the hubs, but more likely the seals that are in the hubs. Either new seals are needed...or new ESOF hubs.

OBTW: The 4x4 light on the dash has NOTHING to do with the hubs engaging or not. It is only for the transfer case engaging. Kind of a "false positive" right?

Good luck...and hope this helps.

biz

 

Biz, re-read this part:

I wouldn't be so quick to say there's something wrong with the hubs.

Sounds like the front hubs wouldn't disengage right away after turning the **** back to 4x2 (2-wheel). Which is normal if the transfer case is stuck in 4x4. When you have strain on the front hubs, and the transfer case won't disengage, the front hubs will remain locked until all torque is gone - which can be a while

Otherwise, Biz is right, sounds like the servo went. However, before spending good money on a new one, I'd make sure it's getting voltage in the right spots. If you don't have a wiring diagram, perhaps someone here (or me) can give you the right wire colors to test if it's actually getting voltage.

Fuses and connectors can look perfectly fine. And not be.

One thing to try:

- Turn off the key
- Turn the **** back to 4x4 HI.
- Start the engine.
- Drive it forward for 50 feet. Then backup 50 feet.
- Without doing anything else, put it in Drive, and turn the **** to 4x2 (2-wheel).
- Let it roll forward 20 feet or so...

If you checked for the running motor after trying and trying to get it out of 4x2, it might totally give up and require a restart to try again. I'm not entirely sure about that but my 2001 seemed to do that to me once when I had too much front/rear torque holding the transfer case in 4x4.

 

I just picked the kids up at school. It won't go into 4WD unless the hubs are in lock. I tried to see if 4WD would work on auto and it doesn't. I think the transfer case motor is shot.

Any advice on how to disconnect the upper electrical connection? Is there a special clip holding it on?

Thanks for all the help so far...

 

krewat --- Might be the hubs too??? Yes...


biz

 

The dash indicator represents the position of the transfer case motor only, there is no indication of operation of the hub vacuum.

Check voltages at the connector of the trannsfer case motor.

If you remove the motor you can also apply 12v to it to the pins to check the movement of the motor.

With the motor off truck, you can crank the transfer case with a socket wrench (3/8 square drive I think) to selection of the 4x4 (2wd-4HI-4LO) and this should light the dash light (with ignition key turned part on).

Be sure to mark the position of the crank nub and the motor spindle BEFORE you play with it so you can put the motor back on afterwards!

On my 2000 F250 I found the motor was powered and turning but the plastic worm gear inside had stripped, so it was making the noise of moving but not actually turning tha transfer case nub.

 

Musicman, thanks for that great post. I just learned something

 

Um, yeah, with that second post, it DOES sound like just the hubs are the problem.

Does the 4x4 light stay on during all of this? If so, you need to fix that first before playing around with the hubs.

The electrical connector for the servo? I think there's a clip on it, that you press DOWN (IN?) and then the connector comes off.

 

The 4x4 light stays on, even though the switch is at 2WD

 

Just to reiterate:

That means the switch on the transfer case is lighting that light, because the transfer case is still in 4x4.

So it's not the hubs.

Definitely sounds like the motor, but I'd make sure it's getting voltage before replacing it.

 

krewat -- I have to agree to disagree! IMHO...I believe it is both the hubs and the motor on the transfer case.

REASON: Big Sky mentioned in a previous post that the hubs do not remain locked while in 4Hi and in the Auto setting. The hubs appear to be loosing vacuum.

biz

 

The vacuum system sends one vacuum pulse to the hubs to lock, once they are locked, the vacuum goes away. So a leak wouldn't make them unlock after locking. The hubs themselves being bad, well, that's something else.

I think what he did was lock the hubs by hand, test it, and then with the system still in 4x4 (or stuck in 4x4), turned them back to AUTO - even with the switch in 4x4, this will unlock the hubs. I've tried it, and it seemed to work that way on mine, and have heard many on this site a few years ago doing the same thing.

ALSO - the GEM will store trouble codes for the ESOF system. It might be worth getting those read to figure out what's really going on.

But I'm still betting on the servo or lack of power to it. Maybe the hubs are NOT working. But the transfer case is stuck and that needs to be addressed first.

The light on the dash is fed by the transfer case, and has nothing to do with whether the hubs are locked or not.

I actually had my ESOF system in a state where the hubs were locked when NOT in 4x4, and unlocked when IN 4x4. I turned off the engine, flipped the **** to 4x4, started the engine, flipped the switch back, and the hubs were back in sync. So it's possible to confuse the system ...

What I mean is, with the transfer case stuck in 4x4, the GEM is confused after so many restarts and switch flips. Who knows what's going on with the hubs right now? We do know, however, that the transfer case is stuck in 4x4 no matter what. So, start there, and check the hubs later.

I still bet the hubs have nothing to do with it.

This could also be a dead GEM module, but I doubt it.

 

I'm baffled. I picked up a transfer case motor, but I figured I better test the old one with a couple of wires off the battery. It works fine.

So I manually reset the transfer case to 2WD and the drive shaft was free. I put the old motor back on. I had my daughter turn the switch to 4WD and the motor worked and the driveshaft is in 4WD. I had her switch it back to 2WD and no go....But after the motor switched it to 4WD, a motor (vacuum???) under the hood over the right front fender well started up. Is this the vacuum pump for the hubs?

Is the pump (if that what it is) the culprit? And if so how could it affect it going back to 2WD or is the transfer case motor just TU?

 

Well after my last post I took it out and it stayed locked in 4x4 mode (hubs on auto)after I switched to 4wd then back to 2wd.

I figured I might as well try the new motor, installed it, but no power at all now. Thought it was a bad replacement but I reinstalled the old one and same deal, no activity. At least I manually switched it to 2wd and am hoping that the weather doesn't ice up the roads again like this past week.


I think I will take it to the shop and have someone with the right equipment look at it and see what the problem is.

Anyone have a problem with the switch on the dash before and what is the GEM?

 

Did you check the fuses? Something might have shorted out when you were switching the motors out.

My guess would be that the gear in your old motor is stripped, but only in one direction, so it can switch into 4x4 but the gear can't catch to try to switch out.