1996 M-1078 transmission. New purchase

[Hibbcase]

Hello, I’ve been stalking and lurking for a while now and finally have a reason to post and ask. I just acquired a 1996 1078 with transmission issues. I’m hoping I can sort them out before having to drop the transmission. Today I discovered some corrosion in the lower connector for the control panel. Does anyone know if I can get a new connector and new pins and simply re-crimp and put a new plug on it. I probably don’t need a new plug and could just put some fresh pins to get things working.
Also while I had it off I peeked in the control box to see if I could find anything weird in there and found a burnt spot on one of the boards in there. It appears to be a burnt mosfet. Does anyone have enough experience with these to know if they’re re-buildable? Worth rebuilding? Or know where I can find a cheap known working used one?
I think mine is a WTEC 2 system.
Thanks!!!

Casey

 

[spankybear]

The TM only show the trans cable as an assembly for the WTECII. No part numbers for the connectors or contacts. It maybe on the US TACOM drawings if you can get a hold of them. The drawing number is 12378540 .

The WTECII ECU Is rebuildable I believe. I'd would use the search function here. That's a lot of smoke to be put back in.

I think Supraman can help if reprogramming is needed. I also believe he has the cable for the WTECII.

 

[fuzzytoaster]

You can send it off to TI for inspection and rebuild. John does a good job and warranties his work for 2 years.

Transmission Instruments

 

[Suprman]

I have good tested ones on hand. It’s cheaper to have yours repaired though, if it’s repairable.

 

[NDT]

Agree with above. HOWEVER, before you blow up a new or repaired controller, make sure you ohm out all the circuits. Follow the Allison manual on how to do this.

 

[Hibbcase]

Agree with above. HOWEVER, before you blow up a new or repaired controller, make sure you ohm out all the circuits. Follow the Allison manual on how to do this.

Thanks for the help fellas, where can one find an allison manual with the proper specs to checking these circuits? Also, are these controller generally reliable or is it a good idea to have a spare?

 

[NDT]

Post # 2:

Need help troubleshooting an issue with my WTECII

So I got the truck up and running after worked through a starting issue. I can select Drive, Revere , and the truck will move. I can select first (1) when the truck is sitting you can feel the trans shift from 2 to 1. I can also select mode. The problem is when I start out and speeding up to...

www.steelsoldiers.com

 

[Skyhawk13205]

Look at the WTEC 2 troubleshooting manual, the connector part numbers and harness buildup should be there.

 

[Hibbcase]

Awesome!!! I had searched through the TM section and didn’t find this. This is exactly what I need to get this harness repaired and tested. Thanks a ton guys!!
Casey

 

[coachgeo]

Awesome!!! I had searched through the TM section and didn’t find this. This is exactly what I need to get this harness repaired and tested. Thanks a ton guys!!
Casey

think this is their last update on the wtech II trouble shoot.... but do not quote me on that.

http://krutzaspreading.com/wp-content/uploads/2018/07/Allison-WTEC-2-Troubleshooting-Manual.pdf

 

[coachgeo]

think this is their last update on the wtech II trouble shoot.... but do not quote me on that.

http://krutzaspreading.com/wp-content/uploads/2018/07/Allison-WTEC-2-Troubleshooting-Manual.pdf

oops I lied.... here is a 2005

https://www.trucktransdiag.com/downloads/4gen.pdf

 

[Hibbcase]

Well I just got my trans controller back from rebuild and it took care of most of my error codes. I’m still left with two, 44 13 and 24 23 I’ve tested all the circuits and can’t seem to find anything wrong, code 4413 is, solenoid short to ground and I’m quite positive none of the solenoids are grounded. I’ve found an old thread that seems to have the same issues that I’m dealing with, and the exact same trouble codes.

First LMTV

Hello all, I have been lurking for some while now, figured I would post up my current situation. I bought this M1078 missing some parts. Mainly WETC II shift selector, VIM, and some double check valves in the brake system. After replacing the shift selector and VIM I have a no start...

www.steelsoldiers.com

I’m thinking my trans has the wrong harness in it. Does anyone know if there is indeed and adapter harness from wtec3 trans harness to wtec2 controller. If not, does anyone know of a known working wtec2 trans harness for sale?

Thanks!!

Casey

 

[Suprman]

Look for old cracking insulation on the cab to trans harness. Take the front grill off. It starts at the drivers side of the hump and goes back.

 

[Hibbcase]

Look for old cracking insulation on the cab to trans harness. Take the front grill off. It starts at the drivers side of the hump and goes back.

I have chased the harness all the way from the bulkhead connector to the trans. I am able to test and get good Ohms for each solenoid at the bulkhead connector and also tested that none of them are grounding out. I’ve isolated and tested all of the solenoid circuit wires from the bulkhead connector to the trans controller and can’t find anything wrong there. If I could find a pinout for the truck side of the trans connector I could isolate and test each wire there as well. Although they test fine from the bulkhead connector so that may be redundant. The only thing I can’t verify is that the trans has the correct harness in it. The symptoms seem the same as a few other guys that have had this issue. The truck has a new looking VIM box, the transmission has a rebuild tag from 2008 and the trans harness looks new-ish but I can’t decipher the part number on this harness. Anything else I could be missing?

 

[Suprman]

There really isnt a wrong harness. Not for trans to cab. Its possible someone installed a trans intended for wtec3 use that would be a cable issue inside the trans though. I believe the tms have a schematic and wiring pinouts.

 

[Hibbcase]

There really isnt a wrong harness. Not for trans to cab. Its possible someone installed a trans intended for wtec3 use that would be a cable issue inside the trans though. I believe the tms have a schematic and wiring pinouts.

Sorry if I was unclear, that’s the issue I think I’m having. I think the trans itself has the wrong harness in it. The valve-body harness.

 

[Suprman]

Maybe you can call allison with the trans serial and they can tell you its configuration. The manual lists some serial number ranges for the trans solenoid pack compatibility

 

[Skyhawk13205]

Well I just got my trans controller back from rebuild and it took care of most of my error codes. I’m still left with two, 44 13 and 24 23 I’ve tested all the circuits and can’t seem to find anything wrong, code 4413 is, solenoid short to ground and I’m quite positive none of the solenoids are grounded. I’ve found an old thread that seems to have the same issues that I’m dealing with, and the exact same trouble codes.

First LMTV

Hello all, I have been lurking for some while now, figured I would post up my current situation. I bought this M1078 missing some parts. Mainly WETC II shift selector, VIM, and some double check valves in the brake system. After replacing the shift selector and VIM I have a no start...

www.steelsoldiers.com

I’m thinking my trans has the wrong harness in it. Does anyone know if there is indeed and adapter harness from wtec3 trans harness to wtec2 controller. If not, does anyone know of a known working wtec2 trans harness for sale?

Thanks!!

Casey

The TMs have a chart regarding the compatibility of harness for WTec III and Wtec II harness. The Wtec 2 manual should also have the same as well. Can you post some pics of the harness pin out, I built a harness for my truck using the Wtec 3 tsm and the electrical manual posted on this site. The harness can also have and ID pin program but I am not 100% sure, can you also post a pic of your TID # on your transmission data plate and TID# on transmission controller data tag and CIN?

good luck

 

[Hibbcase]

I learned a lot today, I made a friend at an Allison transmission repair shop. I was able to confirm that my transmission has a TID3 harness. WTEC 2 transmission controllers, as far as I know, are only compatible with TID1 harnesses. The only difference between these harnesses is which component the TID wire is connected to in the harness. The trans controllers use the TID wire to verify which version of transmission it is hooked to. Newer controllers, post WTEC2, are backwards compatible with all versions of transmissions, older controllers are not forward compatible. The TID3 harness has the TID wire connected to solenoid b in the harness, this explains why I was getting a short to ground error code for that solenoid, but it is only grounded through the TID wire with the controller plugged in. My new friend at Allison helped me find the schematics I needed to figure out how to rewire my harness. All I had to do was move the TID wire from solenoid b to the ground/reference side of the temp sensor and pressure sensor circuitl I was able to do this on the outside of the transmission without dropping the valve body. I finally cleared that pesky 44 13 code and took it for a spin!!!
My next question is if anyone knows if these WTEC2 controllers are ’tunable’? 2 to 3 upshifts seem a little too firm while 3 to 2 downshifts are almost violent. Another thing I was told today is that newer transmissions use a different clutch plate material which can cause firmer shifts. It also still has the military 15w40, will atf make shifts softer or firmer?

 

[Skyhawk13205]

I learned a lot today, I made a friend at an Allison transmission repair shop. I was able to confirm that my transmission has a TID3 harness. WTEC 2 transmission controllers, as far as I know, are only compatible with TID1 harnesses. The only difference between these harnesses is which component the TID wire is connected to in the harness. The trans controllers use the TID wire to verify which version of transmission it is hooked to. Newer controllers, post WTEC2, are backwards compatible with all versions of transmissions, older controllers are not forward compatible. The TID3 harness has the TID wire connected to solenoid b in the harness, this explains why I was getting a short to ground error code for that solenoid, but it is only grounded through the TID wire with the controller plugged in. My new friend at Allison helped me find the schematics I needed to figure out how to rewire my harness. All I had to do was move the TID wire from solenoid b to the ground/reference side of the temp sensor and pressure sensor circuitl I was able to do this on the outside of the transmission without dropping the valve body. I finally cleared that pesky 44 13 code and took it for a spin!!!
My next question is if anyone knows if these WTEC2 controllers are ’tunable’? 2 to 3 upshifts seem a little too firm while 3 to 2 downshifts are almost violent. Another thing I was told today is that newer transmissions use a different clutch plate material which can cause firmer shifts. It also still has the military 15w40, will atf make shifts softer or firmer?

Thanks for sharing that info, sounds like you figured it out. What did the Allison tech think of using a TID3 transmission with a Wtec 2 controller? The TSM gives some warnings about the controller calibration/ shift adaption for different clutch material.

My truck shift pretty hard as well I think it may be due to the oil being thick when cold it may also being due to me having a transcontrolller from another truck.... have you tried driving till up to temp to see if shifts are better? There is a procedure to have the transmission controller relearn the shifts but that is when you change fluid. You may also need to have a relearn because your transmission may have never been driven before with that controller. I think the TM has a procedure to relearn via a keypad command, it is also possible to command via a prolink, you may want to talk to your Allison friend again.