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Discussion Starter #1
I've been reading through threads for months looking for answers to my problem, and I've done several things to try and fix it. However, I'm still at square one and am out of ideas!

Start: I have a '93 EB Bronco with 351, E4OD tranny, BW1356 electric t-case. When in 2wd, vehicle works and drives perfectly. When I engage the 4x4 (Hi or Lo) the truck drives five for a few minutes. When I let off the gas and coast or come to a stop, the drivetrain neutralizes - engine revs, but I have no drive. I have to shift the manual tranny lever back to N, and disengage the 4x4. There is a clunk, and when I move the lever back to drive, the truck drives off and operates just fine.

Recently, I replaced the MLPS, but the truck behaves the same way - fine in 2WD, neutral problem in 4WD.

I have also replaced the hubs to Warn manual lockers, and installed a Shiftster to bypass the electric motor on the t-case. Now, when I manually engage the 4x4 with the Shiftster, the Bronco drives fine for a moment, but then goes neutral - engine revs but no forward drive. No matter what gear I shift to with the lever, my drivetrain is neutralized. I have to shut down the engine, move the Shifster to 2H, and start the truck again. Now it drives just fine in 2WD.

Sorry for the long story. So, does anyone have any ideas of what's up with my Bronco? Anyone have any experience with these symptoms? Do you think it is a problem with my tranny or my t-case?

Just guessing, I think i have an electrical problem with my E4OD?

Thanks. Love the info!!!
 

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I wonder if you have a shift fork issue in the tcase. possibly the detent when you shift the tcase is wore out or broken allowing it to fall into netural?


I know you have a electric shift tcase with that manual shifter thing. Is there a way to see if you can hold the shifter in 4 high?
 

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go to the junk yard and swap transfer cases, all of my electronic operating system failed for my electric TC, so for a cheap fix i ordered my "shiftster" and it works fine, only down fall about it, you have to get under the vehicle to shift it, but for $60 i couldnt pass it up.
 

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sounds to be out of adjustment or broken internals
 

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Discussion Starter #5
I guess it could be something wrong with my t-case. I'm not familiar with how the insides of a t-case really work. The Shiftster has a spring-loaded knob that locks and holds the lever in place for the different drives - 2hi, 4hi, 4lo. Can something internal of the t-case be worn out or broken and allow it to work fine for a minute but then "fall" out of place and let the gears just spin in neutral? Do you think the issue is in the t-case and not the tranny? I would just love to isolate the issue to either the transmission or t-case.

Thanks!
 

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Discussion Starter #6
It's just weird to me that the drivetrain will work fine for a few minutes and then give me problems!!

Thanks, everyone, for the ideas!
 

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yo,
Four Wheel Drive (4X4) General Information, Operation & Troubleshooting TSB 92-1-8 for Bronco, F Series & Ranger (COMPLETE); Includes Electric Shift On The Fly (ESOF) Troubleshooting & Hub Operation; Source: by Ford via Chilton

Take time to go through it, many don't seem to have time and jump around replacing and doing this or that and give up on it.
Diagnosis is on page 9

Check Sensors
on page 10; If the vehicle won’t shift into 4L, check the speed motor position sensor should be checked if it
sensor and the transmission interlocks (neutral or happens frequently.
clutch in). Also check the 4L switch (C3) to see if the module is getting a signal. Be sure to check for corroded connections.

Page 11 - Look for problems with the electric magnetic clutch.
If the racheting or grinding goes on for more than four seconds, there may be a problem with power to the clutch from the shift control module, the clutch ground or the clutch itself. Check the wiring harness as well.



BTW, you wrote; ...have to shift the manual tranny lever back to N, ..."

You have the M5OD Manual Transmission, correct?



same for 87-96; exc for that in 87; power from Fuse 6 (15 amp) to "ELECT SHIFT CONTROL MOD" WHT-PPL and CB 12 (30amp) to "ELECT SHIFT CONTROL MOD" BLK-WHT; SEE A7 and A8 in the 4x4 diagram, it shows those two wires BLK-WHT as BK/W from SHIFT MODULE to P1 BATTY and and WHT-PPL as W/P to P2
 

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Discussion Starter #8
I have the E4OD transmission. I was referring to the column shift lever for selecting P,R,N,D,2,1 (I have the electronic OD on/off button on the end of the shirt lever). Sorry for the confusion, and thanks for the info. I'll definitely go through the info you sent (unless it pertains tot he manual tranny).
 

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I have the E4OD transmission. I was referring to the column shift lever for selecting P,R,N,D,2,1 (I have the electronic OD on/off button on the end of the shirt lever). Sorry for the confusion, and thanks for the info. I'll definitely go through the info you sent (unless it pertains tot he manual tranny).
yo,
Four Wheel Drive (4X4) General Information, Operation & Troubleshooting TSB 92-1-8 applies to both E4OD & M5OD

btw your BW 135 ESOF has its own dedicated speed sensor; some confuse this speed sensor w/the Vehicle Speed Sensor (VSS); also called RABS Sensor & Differential Speed Sensor (DSS)) located in the 8.8 rear differential.

Clutch refers to the ESOF's internal electr. magnetic clutch; except it mentions the Manual trans, such as in; "...The shift module also won't make a shift to 4L or back unless an automatic transmission is in neutral or the clutch is depressed on a manual.."
 

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Discussion Starter #11
I went through the below manual over the weekend and tried several of the suggestions, but I couldn't find any obvious culprits.

Four Wheel Drive (4X4) General Information, Operation & Troubleshooting TSB 92-1-8 for Bronco, F Series & Ranger (COMPLETE); Includes Electric Shift On The Fly (ESOF) Troubleshooting & Hub Operation; Source: by Ford via Chilton.

The problem is, that everything seems to work just fine for a few minutes, and then the system just neutralizes. So, all of the sensors and relays and motors have to be working to get the 4wd engaged initially, but them something goes wrong.

What really frustrates me is that I don't know if the problem is in the t-case or tranny. Is the t-case work out and slipping out of 4wd, or is the tranny computer detecting something and neutralizing the transmission? I don;t know where the neutral action is happening. Does anyone know how to test to see if the neutral state is happening in the tranny or t-case? I looks like the t-case bolts directly to the back to the transmission housing, so I can't see an output shaft or driveline in between the tranny and t-case. Any thoughts.

thanks for all of the help guys! I might just have to suck it up and take it to a tranmission shop to have it looked at an diagnosed. I know how hard it is to try and diagnose a problem with others online!
 

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yo,
Is the OD link Blinking or the CEL lit all the time?

Try a Self Test for Diagnostic Trouble Codes (DTC)s by my pal, BroncoJoe19
The engine temperature must be greater than 50° F for the Key On Engine Off (KOEO) Self-Test and greater than 180° F for the Key On Engine Running (KOER) Self-Test.
Run it around to heat the engine up and shift thru all gears incl Reverse. Then turn off all accessories/lights, etc.

Make sure A/C is off and transmission is in Park (automatic) or in Neutral for a Manual & release clutch.

Do Key On Engine Off (KOEO) portion first.

Look Codes up in my broncolinks.com site using the new Search function.

And Post em here according to:
KOEO
&
KOER

Also try this MLPS Test, Pin-Point in 92-96; from Ford EVTM; "...The negative lead of the multimeter should be placed at the MLPS signal-return ground terminal at the MLPS. Check the resistance of the MLPS: The resistance of the MLPS (pins 30 and 46).." read more
Source: by Ford via alldata & justanswer @ http://ww2.justanswer.com/uploads/paynlessauto/2009-08-28_021637_222222.pdf
"E4OD
No Upshifts, 4th Gear Starts, Harsh Upshifts, Neutrals Out After Shifts"...etc

NOTE - If this test is being done without a break-out box, disconnect the MLPS from the vehicle harness.
 

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Discussion Starter #13
OK, I finally have an answer. I took it to a shop and had a mechanic open it up. It is just worn out, and it would fall into neutral when the vehicle would coast and the system was not under load. Bottom line, I have to rebuild or replace.

Thank you to everyone who offered help and advice. I've learned a ton just from looking into this one issue!
 
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