Transfer case slips out of 4x4

[GDHale]

I have a 1993 bronco with electric shift. Shifts into 4x4 then while driving it slips out of 4x4 and into neutral. Press button and goes back into 4x4. To test the electronics, I put it in 4x4 and unplugged the shift motor then drove it. It slipped out of 4x4 into neutral. Plugged the shift motor back in and put it in 2x4 and drove home. Years ago, it used to slip into neutral when driving in 2x4

 

[Tiha]

Most likely it is a busted shift fork inside the transfercase I believe.

With the motor off I can't imagine what else could do that.

Busted shift forks are pretty common.

 

[miesk5]

Yo GD,
WELCOME!
Recall, BW 1356 Touch-Drive Electric Shift Transfer Case in 93 Bronco & F-Series 4x4 Vehicles Safety Recall 93S65; THE TRANSFER CASES HAVE BEEN BUILT WITH THE WRONG ELECTRIC SHIFT MOTOR. THE TRANSFER CASES CAN SLIP OUT OF THE 4 X 4 HIGH GEAR POSITION DURING COASTING IN FORWARD GEARS OR WITH POWER APPLIED IN REVERSE GEAR. IF THIS OCCURS, THE VEHICLE CAN ROLL FREELY AS IF IN NEUTRAL POSITION REGARDLESS OF THE TRANSMISSION GEAR SELECTOR POSITION. THIS CANRESULT IN LOSS OF VEHICLE CONTROL AND AN ACCIDENT. REPLACE DEFECTIVE TRANSFER CASES WITH THE CORRECT VERSION.
See Recall info below.

1356 Electric Shift Troubleshooting & Repair - BEST PROCESS! @ http://web.archive.org/web/20100923...rford.org/documents/electric1356/elec1356.htm
Source: by Dustin S (Dustball, Mellow Yellow, Mr. Laser Boy)

●
Find out if speed control, if equipped, recall work is completed.
If you still have concerns about Recalls, please contact the Customer Relationship Center:
US: 800-392-3673 | CA: 800-565-3673
Note: 3673 spells "FORD" on phone keys
For the hearing- or speech-impaired: Please contact the Telecommunication Relay Service by dialing 711.
... have VIN ready.
"Summary: ON CERTAIN PICKUP TRUCKS, PASSENGER VEHICLES, SPORT UTILITY VEHICLES, AND MOTOR HOMES CHASSIS, THE SPEED CONTROL DEACTIVATION SWITCH MAY, UNDER CERTAIN CONDITIONS, LEAK INTERNALLY AND THEN OVERHEAT, SMOKE, OR BURN. THIS COULD RESULT IN AN UNDERHOOD FIRE."
See this guide by jowens1126 to confirm recall status @ 93 & 94-96 Cruise Control Recalls Repair
Note that the 93 recall is different than 94-96.

Here is the 1993 Bronco Dealer Brochure in Google Drive @ 93Bronco.pdf

1993 Bronco Dealer Training Video via silver70 @

1993 Bronco, Venezuela Commercial @

Haynes Red Manual for 80-95 Bronco & F Series @ Hanes guide 80-96 bko f series.pdf via BroncMom
Al

 

[GDHale]

Thanks for the info. I have been dealing with this for years and no one has ever had any idea. I will post what the fix was when I have it all worked out.

 

[wyo58]

Okay to add to this thread, I have 1992 Bronco, manual hubs, and shift on the fly. 2wd has never been an issue as well as 4wd low. However it does slip out of 4wd high, and it is only on coast going forward. The 4x4 light stays on but it disengages like no power to the wheels. You stop and put it in park and it chatters on the parking pawl, so the trans is spinning. Transfer case has been replaced (reman), as well as the shift motor. The connector has been cleaned from all the old ford electric grease and all connectors look good. I have put the unit in 4wd high and pulled the shift motor and it is dead on the mark. I have also tested it without the manual hubs and not been able to get it to slip out ( maybe not enough time ). It has never done it in 2wd or 4wd low. So I'm at a loss, electrically everything seems to be working perfectly. Now I'm wondering about the coil on the front drive line, if it is some how doing this. Any help would be appreciated.

 

[Tiha]

Not sure what you mean by coil on the front axle. Can you explain more?

It really has to be your transfer case. Put it in 4 hi. Take the motor off and go for a drive and that will eliminate any electrical problem chances. Leaving only mechanical.

 

[wyo58]

It is an electric clutch that spins up the front drive line to match the rear speed, hence shift on the fly. The original transfer case did exactly the same thing as the reman is doing. So I agree in eliminating the electrics from the equation to figure it all out.

 

[Tiha]

I would have to say I have never seen one. That is interesting.

 

[wyo58]

All bw 1356 electric shift t cases have them.

 

[notjuice]

It is an electric clutch that spins up the front drive line to match the rear speed, hence shift on the fly. The original transfer case did exactly the same thing as the reman is doing. So I agree in eliminating the electrics from the equation to figure it all out.

Hello,
Did you ever resolve your issue? I have a similar issue and have not successfully resolved it in 3 years…I have concluded it is definitely electrical and likely the electro magnetic clutch in the TC. Which remains under power even if you take off the shift motor.
Any information would be appreciated.
I also have gone through the trouble shooting info from miersk5, though the shop said they couldn’t test it on the road when it pops into neutral…and wanted to tow it back to shop which was going to be expensive, I don’t think they were very interested in doing it…I live in a small town in Central Washington and have run out of shops and options…very frustrating

 

[notjuice]

I would add I have replaced the TC twice, the shift motor, neutral safety switch and the shift control module…

 

[notjuice]

Thanks for the info. I have been dealing with this for years and no one has ever had any idea. I will post what the fix was when I have it all worked out.

Did you ever get this issue fixed? i have the same problem…

 

[wyo58]

Did you ever get this issue fixed? i have the same problem…

So far not completely resolved, however I have unplugged the rabs module but have not had the time to see if that is causing the issue. My rabs check light was on and I decided to study the schematic of the rabs module more. Oddly enough one on the leads from the rabs goes to the shift switch and only to the 4wd side. I will let you know if that was the culprit.

 

[Tiha]

It is an electric clutch that spins up the front drive line to match the rear speed, hence shift on the fly. The original transfer case did exactly the same thing as the reman is doing. So I agree in eliminating the electrics from the equation to figure it all out.

Need to clarify a couple things.

The BW1356 is the only transfercase used from 87-95 that I was aware of. There may be others, but you said you had the 1356 so let's work off that.

The 1356 has no provisions for an electric clutch or any electronics inside the case itself.

For actuation you had two options, electronic shift or manual shifting. Usually the half tons got the electronic shift while the 3/4 and 1 tons got the manual shifting. I have no idea why.

Shift on the fly simply comes from driving with the front hubs locked in. If they are locked the front driveshaft will always be spinning at the proper speed to engage and disengage 4x4 whenever you want.

The automatic hubs, if you still have them. Engage when you put in 4x4 and do not disengage until you change direction. Allowing you to go in and out of 4x4 as desired.

You could very well have electrical issues causing your transfercase to go in and out of 4x4.

I am pretty sure on my son's 94 we took the shift motor off and manually shifted it to 4x4 and drove it around to verify it was electrical and not mechanical.
It was electrical. After repeated attempts at replacing the motor and control module multiple times. We did not resolve the problem until we got a shift motor and module from the same donor vehicle. Not supposed to mater, but it did for us.

On my 1995 1 ton that had a failure, it would pop in and out of 4x4. Maybe skip was a better word. It is a manual shift. That failure was from a broken shift fork, which actually was from a failed **** pump. I am not sure what year they changed over, but my 1995 had plastic shift forks. The used TC I bought for parts was from a 1988 and it had metal shift forks.

Here is a parts breakdown of the 1356. Pretty simple. Just have to narrow it down between electronic or mechanical failure by manually operating it.

 

[wyo58]

Need to clarify a couple things.

The BW1356 is the only transfercase used from 87-95 that I was aware of. There may be others, but you said you had the 1356 so let's work off that.

The 1356 has no provisions for an electric clutch or any electronics inside the case itself.

For actuation you had two options, electronic shift or manual shifting. Usually the half tons got the electronic shift while the 3/4 and 1 tons got the manual shifting. I have no idea why.

Shift on the fly simply comes from driving with the front hubs locked in. If they are locked the front driveshaft will always be spinning at the proper speed to engage and disengage 4x4 whenever you want.

The automatic hubs, if you still have them. Engage when you put in 4x4 and do not disengage until you change direction. Allowing you to go in and out of 4x4 as desired.

You could very well have electrical issues causing your transfercase to go in and out of 4x4.

I am pretty sure on my son's 94 we took the shift motor off and manually shifted it to 4x4 and drove it around to verify it was electrical and not mechanical.
It was electrical. After repeated attempts at replacing the motor and control module multiple times. We did not resolve the problem until we got a shift motor and module from the same donor vehicle. Not supposed to mater, but it did for us.

On my 1995 1 ton that had a failure, it would pop in and out of 4x4. Maybe skip was a better word. It is a manual shift. That failure was from a broken shift fork, which actually was from a failed **** pump. I am not sure what year they changed over, but my 1995 had plastic shift forks. The used TC I bought for parts was from a 1988 and it had metal shift forks.

Here is a parts breakdown of the 1356. Pretty simple. Just have to narrow it down between electronic or mechanical failure by manually operating it.

View attachment 32232

Your drawing is of a bw 1354 which is a manual shift. the one I posted hopefully is of a bw 1356 part number 64

 

[notjuice]

Your drawing is of a bw 1354 which is a manual shift. the one I posted hopefully is of a bw 1356 part number 64

wyo58, Yes you are correct, the clutch is part 23. Tiha, the BW 1356 has a magnectic clutch, there are 3 wires that go into the TC. One is for the speed sensor and one is for the clutch. It is controlled at the shift module thru connector C1...Pin 1 and pin 10 on the transfer case shift motor connector are the two suspect connections...I attached a PDF of the pin point testing the magnetic clutch is on the last couple pages...
I think one of the wires is broken, or i have a bad ground...of interest is the fact that the ABS and speed sensor also are part of theses wire harness and I have the ABS light on on the dash...though the ABS light came on way after the 4 x4 issue so not sure it is related?

 

[Tiha]

They all don't have the coil. Ford only used the 1356 in everything. Maybe there are internal differences but that seems kind of silly.

Manual shift or electric shift they were still a 1356.

That is certainly interesting.

 

[wyo58]

They all don't have the coil. Ford only used the 1356 in everything. Maybe there are internal differences but that seems kind of silly.

Manual shift or electric shift they were still a 1356.

That is certainly interesting.

I would have to agree Tiha it is kind of silly. Their thinking was If you are going say 30 miles an hour with auto hubs, it energizes the coil which starts to bring the front drive shaft up to the speed of the what the rear shaft is spinning. Then it shifts into 4wd, that is the theory of it any way. Keep in mind the hubs are auto that came on the vehicle originally, so the front shaft is dead. Now with manual hubs already locked in the front shaft will be spinning same as the rear shaft, so it shifts in fairly fast. It is all because of the auto hubs and the ease of shifting on the fly (you dont have to get out to lock the hubs). I agree all 1356's are either manual shift or shift on the fly. But if it came with auto hubs it has the coil assembly in it.

 

[wyo58]

wyo58, Yes you are correct, the clutch is part 23. Tiha, the BW 1356 has a magnectic clutch, there are 3 wires that go into the TC. One is for the speed sensor and one is for the clutch. It is controlled at the shift module thru connector C1...Pin 1 and pin 10 on the transfer case shift motor connector are the two suspect connections...I attached a PDF of the pin point testing the magnetic clutch is on the last couple pages...
I think one of the wires is broken, or i have a bad ground...of interest is the fact that the ABS and speed sensor also are part of theses wire harness and I have the ABS light on on the dash...though the ABS light came on way after the 4 x4 issue so not sure it is related?

I will try it this weekend with the rabs module unplugged and let you know if it stops the 4wd slip out. I'm not sure if I mentioned this before but mine has never popped out of low range, that's why i'm leaning toward the rabs module doing something with the shift on the fly system.

 

[Tiha]

I agree all 1356's are either manual shift or shift on the fly. But if it came with auto hubs it has the coil assembly in it.

It just kinda shocked me. I am old and can't believe I have never ran into that or even heard it before.

Was really hoping someone would come along with a model break down, but forums like this are not what they used to be.