Transfer Case Shift Motor Help

[TXFishin]

2012 Expedition EL Limited 4X4

Would a faulty transfer case shift motor, shift in 4A, 4H, and 4L, but not shift into 2WD?

When I shift into 2WD, the IWE's disconnect the axles as they should, each wheel turns freely, all that is working fine, no vacuum leaks, no bad check valves, no bad solenoid, everything seems perfect as far as common issues go.

When I shift into 4A, 4H and 4L, that all seems to work fine as well, the IWE's engage as they should, etc..

However, when i shift into 2WD, the front drive shaft, front differential, and half axles are still engaged and spinning.

It's not a "fluid" type rotational engagement, it matches the RPM of the rear drive shaft.

It's as if I'm running in 4A, 4H, or 4L with the IWE's disengaged letting the front wheels turn free.

My understanding, in 2WD mode, the front drive shaft, along with the half-axles and differential should not be engaged.

According to what I've read, in 2WD everything forward should be disengaged, to reduce wear and increase mpg slightly.

Has anyone experienced anything like this?

Is there a straight forward way to test the transfer case shift motor?

If I remove the transfer case motor, leave the electrical connected, should I see it turn when I shift through the gears?

 

[coupe11]

Can't say about the Fords. Had a Chevy Blazer (mid 90's) act up one time.

In 2WD, if I hit the button for 4WD High it would light up the 4WD high indicator, then go back to 2WD and light that indicator light up again.

If I stopped, hit the 4WD Low button it would light up the 4WD Low indicator and say in 4WD Low. Then, only when in 4WD Low, I could press the 4WD High button and it would light up the 4WD High indicator and stay in 4WD High. I could, when 4WD no longer needed, then hit the 2WD button and light up the 2WD indicator and go back to 2WD.

Bad pick up strip (can't remember the name of that piece) in the motor that switched from the 2 to 4 hi to 4 low. If the sensors cannot pick up the location where the motor should stop then it would just go back to 2WD. Programmed that way. For some reason it could pick up the position when moving in the direction from 4WD Low to 4WD high, but not the other direction.

Again, it's been years, but there was a way to check the unit and I confirmed it was the motor and replaced it and that fixed it.

May be something similar on the Expedition. Electronics are great, till they aren't. That Blazer was a PITA to get to that shift motor and replace it, hope the Expedition is easier (in case I ever have to do it on the 14 I bought last year.)

Good luck with it.

 

[TXFishin]

Can't say about the Fords. Had a Chevy Blazer (mid 90's) act up one time.

In 2WD, if I hit the button for 4WD High it would light up the 4WD high indicator, then go back to 2WD and light that indicator light up again.

If I stopped, hit the 4WD Low button it would light up the 4WD Low indicator and say in 4WD Low. Then, only when in 4WD Low, I could press the 4WD High button and it would light up the 4WD High indicator and stay in 4WD High. I could, when 4WD no longer needed, then hit the 2WD button and light up the 2WD indicator and go back to 2WD.

Bad pick up strip (can't remember the name of that piece) in the motor that switched from the 2 to 4 hi to 4 low. If the sensors cannot pick up the location where the motor should stop then it would just go back to 2WD. Programmed that way. For some reason it could pick up the position when moving in the direction from 4WD Low to 4WD high, but not the other direction.

Again, it's been years, but there was a way to check the unit and I confirmed it was the motor and replaced it and that fixed it.

May be something similar on the Expedition. Electronics are great, till they aren't. That Blazer was a PITA to get to that shift motor and replace it, hope the Expedition is easier (in case I ever have to do it on the 14 I bought last year.)

Good luck with it.

Thanks for the information!

The shift motor it self is very easy to get to and change out, but at around $265 it's an expensive test.

It seems like it shifts to everything except 2WD based on the fact the front drive shaft and axles never disconnect, only the wheel hubs.

It may not be the best way to test, but I un-bolted the shift motor, used a sharpie to mark it, and with it still connected it did not move at all shifting through the gears.

The dash lights showed correct for the switch, 2WD, 4H, 4L, etc.. but the shift motor never moved position.

So the next question, does the shift motor is what changes the transfer case into 4L or is there another mechanism that does that?

If the shift motor doesn't move then how does it shift to 4L?

It could be stuck in 4A or 4H and the hubs disconnect the wheels, when i shift out of 2WD it locks the hubs, and a 2nd mechanism shifts to 4L when i select that? I'm not sure yet

 

[07navi]

Your front diff, shaft, and axles are being pushed from the transfer case and not pulled by the wheels (like you said) so concentrate on the shift motor and the inner workings of the T-case plus the switch on the dash. We can't diagnose it from here so look into those areas. Maybe someone will chime in that had a similar problem, also you should get those 2 big red shop manuals for that year, there is troubleshooting info in there on problems like that.

 

[mnachreiner86]

What’s it doing while driving that causes you concern?


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[07navi]

What’s it doing while driving that causes you concern?


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Everything up front is spinning all the time which just adds wear and hard on MPG's.

 

[mnachreiner86]

Is it making noise? Grinding? What is it doing? Everything turns all the time, not true of the older ones (I’m coming from a 2000). For someone that just had the front diff rebuilt at 209k I’m pretty familiar with how they work at this point. Compared to the previous expeditions and f150s it’s a constant velocity shaft as opposed to a standard front driveshaft and everything is always turning when you’re rolling, it’s only under power when in 4A, 4H 4L. If the iwes, solenoids and check valve are operating as they should with no vacuum leaks and you’re fine with no grinding, everything is working as it should. I had a grinding in 2 hi that only got worse in 4wd, opposite of what iwe issues would present. Turned out to be toasted carrier bearings in the front diff. Initially sounded like a wheel bearing to me and after chasing and replacing could feel it in the diff itself under my feet when it was bad enough. Long story short if everything in the IWE system works and shifts to all of the modes fine and you don’t have metallic noise, be happy and drive it.


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[07navi]

Is it making noise? Grinding? What is it doing? Everything turns all the time, not true of the older ones (I’m coming from a 2000). For someone that just had the front diff rebuilt at 209k I’m pretty familiar with how they work at this point. Compared to the previous expeditions and f150s it’s a constant velocity shaft as opposed to a standard front driveshaft and everything is always turning when you’re rolling, it’s only under power when in 4A, 4H 4L. If the iwes, solenoids and check valve are operating as they should with no vacuum leaks and you’re fine with no grinding, everything is working as it should. I had a grinding in 2 hi that only got worse in 4wd, opposite of what iwe issues would present. Turned out to be toasted carrier bearings in the front diff. Initially sounded like a wheel bearing to me and after chasing and replacing could feel it in the diff itself under my feet when it was bad enough. Long story short if everything in the IWE system works and shifts to all of the modes fine and you don’t have metallic noise, be happy and drive it.


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No supposed to all turn all the time, that's his problem.