Help…. Completely lost on this…. Transmission or Transfer Case

[TBorchardt]

Hi everyone.
New member and need some guidance.

I bought and rebuilt a 99’ explorer sport 4.0SOHC for my kid. He drove to school the other day and said everything was fine, but after school the vehicle was “acting weird”.

So I went to check it out. The transmission is shifting like the transfer case is in 4L. The O/D of light is also flashing. It doesn’t turn rough like it would in 4wd, but have not put it on jackstands to verify that it truly isn’t. It drives like it has since I rebuilt it.

I put the scanner on it and got a ton of codes (B1359, C1230, C1102, P1729, P1838, P1846, P1850, P1867 & P1891)

There was not and still is not a CEL or ABS light on.

The GEM does nothing when you try to shift it from AUTO to 4H or 4L.

Where do I begin to try to figure this out?

 

[Pete Deering]

Hi everyone.
New member and need some guidance.

I bought and rebuilt a 99’ explorer sport 4.0SOHC for my kid. He drove to school the other day and said everything was fine, but after school the vehicle was “acting weird”.

So I went to check it out. The transmission is shifting like the transfer case is in 4L. The O/D of light is also flashing. It doesn’t turn rough like it would in 4wd, but have not put it on jackstands to verify that it truly isn’t. It drives like it has since I rebuilt it.

I put the scanner on it and got a ton of codes (B1359, C1230, C1102, P1729, P1838, P1846, P1850, P1867 & P1891)

There was not and still is not a CEL or ABS light on.

The GEM does nothing when you try to shift it from AUTO to 4H or 4L.

Where do I begin to try to figure this out?

(A) B1359 FORD code possible causes. Faulty Ignition Switch; Ignition Switch harness is open or shorted; Ignition Switch circuit poor electrical connection; Faulty Smart Junction Box (SJB) Start by checking the "Possible Causes" listed above. …

(B) Code C1230 Ford Description. The Anti-Lock Brake System (ABS) Module monitors the Rear Anti-Lock Brake Sensor.

(C) If your vehicle is suffering from a C1102 code, the issue may lie with a faulty ABS sensor. Corroded, damaged, faulty and otherwise poorly installed circuitry may be to blame for this circuit failure. In some rare cases, the ECU itself may be faulty, mistakenly reporting the trouble code as a result. Because ECUs seldom report trouble codes falsely, it should only be consider

(D) P1729 Ford Code Mean? 4x4 Low Switch Error is the generic description for the P1729

(E) P1838 code, Transmission Transfer Case Shift Motor Circuit Failure
The Engine Control Module (ECM) monitors the Transmission Transfer Case Shift Motor. The ECM sets the OBDII code when the Transmission Transfer Case Shift Motor is not to factory specifications.

(F) P1846 Ford Code Mean? Transmission Transfer Case Contact Plate 'A' Circuit Failure is the generic description.

(G) P1850 Ford Code - Transmission Transfer Case Contact Plate 'B' Circuit Failure.

(H) P1867 ford code contact plate..

(I ) P1891 contact plate ground.

Response to your question.
1. Check the connector at the TC shift motor for corrosion and damage.
2. Check the TC Shift Motor ground there. it is by itself.
3. O/D light flashing could be from a broken wire Or a bad ground wire at the TC shift motor.
4. The issue in A above is a Faulty Ignition Switch. Replace it.
5. There is a multi function module behind the radio with all the above Input function listed above. There are four connectors on it. You want the 22 pin connector. Marked with two lines in picture.
6. Lift the front wheel off the ground and spin one wheel by hand. And see if both front wheel turn. 4 wheel high or low will turn those wheels. Low is just a gearing thing in the transfer case.
Did your son put in low gear and the ground wire fail?

Check all wiring. This is incomplete information for now.

 

[EB4X]

There was not and still is not a CEL or ABS light on.
The bulbs are probably just burned out....not totally uncommon.

 

[Mbrooks420]

There should be nothing audible happening between auto and high.

 

[C420sailor]

You can pull the shift motor and visually ascertain which range it is in…you can also manually shift between ranges this way.

This many OBD codes…either an electrical issue or the shift motor suffered some kind of catastrophic/multiple failure.

I’d get under the truck and check the harnesses and connectors from the TC all the way up. Test for solid grounds at the motor. A single bad ground can cause multiple faults. So can a melted harness.

 

[410Fortune]

after checking out all the wiring going to the transfer case maybe drain a little transfer case fluid and have a look at it. Should be. Bright red, if it is dark or smells burnt, small pieces of white nylon then the t case may have bit the dust. However right now it looks as if the transfer case motor was unplugged? Or wiring connector damaged? Physical inspection is needed

 

[TBorchardt]

Thanks everyone. I drive for a living, so when I get home Thursday evening, I will start in on these suggestions.

 

[TBorchardt]

after checking out all the wiring going to the transfer case maybe drain a little transfer case fluid and have a look at it. Should be. Bright red, if it is dark or smells burnt, small pieces of white nylon then the t case may have bit the dust. However right now it looks as if the transfer case motor was unplugged? Or wiring connector damaged? Physical inspection is needed

He claims he did nothing. But we all know how kids are.

I was under it this past weekend and everything looks plugged in and intact.

 

[TBorchardt]

(A) B1359 FORD code possible causes. Faulty Ignition Switch; Ignition Switch harness is open or shorted; Ignition Switch circuit poor electrical connection; Faulty Smart Junction Box (SJB) Start by checking the "Possible Causes" listed above. …

(B) Code C1230 Ford Description. The Anti-Lock Brake System (ABS) Module monitors the Rear Anti-Lock Brake Sensor.

(C) If your vehicle is suffering from a C1102 code, the issue may lie with a faulty ABS sensor. Corroded, damaged, faulty and otherwise poorly installed circuitry may be to blame for this circuit failure. In some rare cases, the ECU itself may be faulty, mistakenly reporting the trouble code as a result. Because ECUs seldom report trouble codes falsely, it should only be consider

(D) P1729 Ford Code Mean? 4x4 Low Switch Error is the generic description for the P1729

(E) P1838 code, Transmission Transfer Case Shift Motor Circuit Failure
The Engine Control Module (ECM) monitors the Transmission Transfer Case Shift Motor. The ECM sets the OBDII code when the Transmission Transfer Case Shift Motor is not to factory specifications.

(F) P1846 Ford Code Mean? Transmission Transfer Case Contact Plate 'A' Circuit Failure is the generic description.

(G) P1850 Ford Code - Transmission Transfer Case Contact Plate 'B' Circuit Failure.

(H) P1867 ford code contact plate..

(I ) P1891 contact plate ground.

Response to your question.
1. Check the connector at the TC shift motor for corrosion and damage.
2. Check the TC Shift Motor ground there. it is by itself.
3. O/D light flashing could be from a broken wire Or a bad ground wire at the TC shift motor.
4. The issue in A above is a Faulty Ignition Switch. Replace it.
5. There is a multi function module behind the radio with all the above Input function listed above. There are four connectors on it. You want the 22 pin connector. Marked with two lines in picture.
6. Lift the front wheel off the ground and spin one wheel by hand. And see if both front wheel turn. 4 wheel high or low will turn those wheels. Low is just a gearing thing in the transfer case.
Did your son put in low gear and the ground wire fail?

Check all wiring. This is incomplete information for now.

View attachment 445530

View attachment 445531

He claims he didn’t do anything other than get in it and drive. He actually questioned if someone at school messed with his car. Granted, we all know how kids can be.

Now that 22 pin connector, is that all the wiring from the GEM to the tc?

 

[Pete Deering]

He claims he didn’t do anything other than get in it and drive. He actually questioned if someone at school messed with his car. Granted, we all know how kids can be.

Now that 22 pin connector, is that all the wiring from the GEM to the tc?

First check the ground at the transfer case.
There around 20 ground on the explorer. Check the two ground wires under the driver and passenger doors.
The frame to the body.

Now that 22 pin connector, is that all the wiring from the GEM to the tc? Yes
See pictures for wiring

 

[TBorchardt]

Update:

So after jacking up the car, only one wheel spins if I rotate it by hand.

Both ground cables under the doors are toast. Picked up new ones at the parts store tonight.

I pulled the tc shift motor off and had the wife go in the car with ignition on, enigine off and turn the 4x4 selector as I laid under the car watching the shift motor. No signs of anything happening down there.

When I pulled the tc shift motor, the rod that engages the shift motor, was pointing to the L. I’m assuming here that that rod is shaped like a wedge and the point of the wedge is the gear the tc is in correct?

Now I also grabbed onto that rod and could turn it freely with my fingers with little to no effort. Didn’t seem right to me.

My light died so tomorrow I plan to drain the fluid in the tc and inspect. Install the new ground cables under the doors and proceed to figure this out.

 

[Pete Deering]

Update:

So after jacking up the car, only one wheel spins if I rotate it by hand.

Both ground cables under the doors are toast. Picked up new ones at the parts store tonight.

I pulled the tc shift motor off and had the wife go in the car with ignition on, enigine off and turn the 4x4 selector as I laid under the car watching the shift motor. No signs of anything happening down there.

When I pulled the tc shift motor, the rod that engages the shift motor, was pointing to the L. I’m assuming here that that rod is shaped like a wedge and the point of the wedge is the gear the tc is in correct?

Now I also grabbed onto that rod and could turn it freely with my fingers with little to no effort. Didn’t seem right to me.

My light died so tomorrow I plan to drain the fluid in the tc and inspect. Install the new ground cables under the doors and proceed to figure this out.

Do not drain the fluid yet. That Has nothing too do with the shift motor working.
Disconnect the plug and use a test light or similar item and see if you are getting a signal there. Ground to a good ground on one side and test each wire.

 

[C420sailor]

IIRC, the shift mechanism should be easy to move

It’s likely the motor, wiring, or GEM. Troubleshooting time.

 

[410Fortune]

Ummmm
Shifting from low range with your fingers? I dunno about that. For me a pair of plyers is required to move that little stub and it takes some effort, it does not just flop from low to neutral and so forth.
Yes it was pointed to low range the tip of the arrow indicates what gear you are in.

I would for sure drain some
Fluid you need to have a look in there. A failed control trac t case will have dark fluid and nylon bits in the fluid, this is a tale tale sign the little nylon guide inside the case is toast, common failure. With the low and high lights flashing at you, and the way it was driving I suspect a toasted control trac t case.

I have seen this 100 times with the 96/97 model year control trac cases. And a new one with low miles is basically impossible to find, which is why I often install the back half of the bad t case that includes the vss and drive gear, onto a later model t case like 98-01.
Or do a control trac delete and install a 1354m or 1354e (and change the front d shaft to the 98-01 style)

 

[TBorchardt]

Okay got some time again today to work on the explorer a bit.

Put the new body ground cables on.

I did drain the fluid to inspect. Wanted to change the fluid anyway and hadn’t gotten to it. I do not see any sign of Teflon pieces in it. The fluid was dark but didn’t smell burnt or anything.

I took my test light under the car with key on and the selector in the dash to high range. Light on the dash came on and I probed the tc motor plug. On the picture I attached, the white lines I marked on the pin holes indicates an “on” test light. The one entire side of the plug is a pulsing test light.

I then came back out from under the car and put the selector into low range. The light in the dash remained on for high range and the low range never light up. (I put all new bulbs in the dash the other day now so I know all of the indicators should work if they get signal)

Now I should mention the other day when I took the tc motor off and moved the tc shaft to the “N”, I took the car for a drive down the block. It is still doing the same thing as when I originally posted.

What’s my next move?

 

[C420sailor]

I may be wrong…but I believe that placing the TC in N should result in the truck not being able to move under its own power. This is the position the dealer-installed flat tow kit exploits.

The fact that yours behaves like it is still in 4L isn’t good…BUT I MAY BE WRONG.

Did you try it in H?

 

[TBorchardt]

I may be wrong…but I believe that placing the TC in N should result in the truck not being able to move under its own power. This is the position the dealer-installed flat tow kit exploits.

The fact that yours behaves like it is still in 4L isn’t good…BUT I MAY BE WRONG.

Did you try it in H?

I have not. I moved it to the “N” and left it there.

 

[TBorchardt]

Another question, I was going to order a new tc motor so I have it here on hand. No parts stores in town have it so I was just going to purchase from rock auto. The wiring is different on what I can buy versus what I have.

The new one looks as the wiring is only for the tc motor. Mine has the wiring shown in the other 2 photos all going with it in the same connection on the motor side of the plug.

What’s the deal with the wiring in those 2 photos?

 

[C420sailor]

at this point I would hold off and make sure the TC is mechanically sound first.

What I worry is that an internal mechanical failure may have damaged the shift motor.

If I were king for a day, I’d manually shift ranges and see if the case does what it should do. If it does, and the connector is getting the proper signaling, then I’d order a shift motor.

 

[C420sailor]

I believe you have an older case with a VSS (speed sensor) which is what those three wires are feeding.

I assume that has a different shift motor due to the harness.

Smarter guys will chime in here. TCs aren’t my forte