New owner of 1997 LMTV

[Blairg]

Sounds like it, min spec is 2.8.

And out of morbid curiosity where might that be?

 

[NDT]

And out of morbid curiosity where might that be?

I don't understand your question. I got the 2.8 number from the Allison WTECII Troubleshooting manual. If you don't have it, PM me your email and I'll send it. I thought is was here on the site somewhere.

 

[Blairg]

I don't understand your question. I got the 2.8 number from the Allison WTECII Troubleshooting manual. If you don't have it, PM me your email and I'll send it. I thought is was here on the site somewhere.

sorry. The G solenoid?

 

[NDT]

Here I attached it here.

 

[NDT]

Oh the G solenoid? In the pan.

 

[tennmogger]

Did you check the two big connectors at the rear of the dash shifter panel? Have to pull the whole dash to get to those plugs. Partial disconnect causes lots of error codes, being very misleading (like multiple solenoid failures). I found that out the hard way alongside a highway when the tranny lost its mind. Be sure the heavy grounding braid from the box is secure too.

 

[Blairg]

I did take the dash apart and checked the plugs. I will need to check again just to make sure. Not much room to get your hands behind there.
Heavy grounding strap? I found one grounding the cab to chassis and it was tight. Also the alternator grounding strap was tight. What box are you mentioning?
Thanks
Blair

 

[coachgeo]

I did take the dash apart and checked the plugs. I will need to check again just to make sure. Not much room to get your hands behind there.
Heavy grounding strap? I found one grounding the cab to chassis and it was tight. Also the alternator grounding strap was tight. What box are you mentioning?
Thanks
Blair

tight is not the issue..... "CLEAN" is the issue. they can be tight yet have corrosion in contact area. With this in mind..... check for corrosion at the connections on the Rev. Polarity Connection block under the spare tire (if it is A0, On A1's it is a different box with additional functions, different name, same location)

 

[Blairg]

So...after a bit a messing around with it myself. Making sure harness's looked good, no breaks, everything connected and appearing clean and corrosion free I called our local diesel shop to make an appointment. Lucky enough to have a great one that is local and people who trust to send our fire equipment to. First step was to bring out somebody with a computer to see what could be done with that. Was able to hook up to the truck computer but was unable to read much or clear the codes that were stored in the computer to be able to shift. We then checked to make sure everything was getting power and continuity of the harness between the Vim and computer.
So that leads us back to the original idea that the problem still is the G solenoid. Going to have the truck brought in next week to fix that and service the transmission. Also going to change it over to Allison recommended ATF. We shall see.
Blair

 

[NDT]

The Army didn't drain the Allison just for s___s and grins. They were about to pull it when someone decided coding it out was funner.

 

[Blairg]

A quick update...Finally got the truck into the shop with the idea to drop the pan and get to the solenoids. G solenoid was throwing a code and when checked proper ohms were not found. So today when the mechanic dropped the pan he found a part of the wiring harness had been crushed when the pan was installed by somebody causing the short to the G solenoid. He said he coudn't easily figure out how to remove the pan completely from the transmission but since he was able to fix the wire he didn't explore that too much. He changed filters and refilled with ATF.
So here's where we are now... WTEC still has codes in the system and mechanics computer cant seem to clear them. Is their a way to reset the computer without the use of the PC?
Blair

 

[coachgeo]

A quick update...Finally got the truck into the shop with the idea to drop the pan...was able to fix the wire he didn't explore that too much. He changed filters and refilled with ATF.
So here's where we are now... WTEC still has codes in the system and mechanics computer cant seem to clear them. Is their a way to reset the computer without the use of the PC?
Blair

have you downloaded the generic WTechII pdf yet? Think it tells you how to do it thru the keypad

 

[Blairg]

I have downloaded it and went through it. Keypad doesnt seem to clear the codes. Was hoping to start from zero if we could get rid of the old codes , now that we have all the solenoids within spec ohm wise.

Blair

 

[Suprman]

I think you hold the mode button while in code reading mode till the codes clear.

 

[coachgeo]

It's amazing what one can find with an internet search....

https://www.youtube.com/watch?v=KKqPDQL6YHY

 

[wandering neurons]

Per the Allison 3000/4000 WTEC-II series troubleshooting manual:
WTEC II ELECTRONIC CONTROLS TROUBLESHOOTING MANUAL
NOTE: If a DO NOT SHIFT condition is present at this time, the shift lever should remain in the same position where it was when the DO NOT SHIFT was detected. If the lever is moved, a continuous tone will be heard until the lever is returned to the correct position.
NOTE:If an oil level sensor is present, then fluid level will be displayed first.
Diagnostic code display is achieved by depressing the ⇑ (Up) and ⇓ (Down) arrow buttons or the DISPLAY MODE button a second time.The code list position is the first item displayed, followed by the main code and the Subcode. Each item is displayed for two seconds. The two second item display cycles continuously until the next code list position is accessed. The following list represents the display cycle using Code 25 11 as an example:1. Code list position — d12. Main code — 253. Subcode —114. Cycle repeats — d1
To view the second, third, fourth, and fifth positions (d2, d3, d4, and d5), momentarily press the MODE button as explained above.Momentarily press the MODE button after the fifth position is displayed to restart the sequence of code list positions.An active code is indicated by the MODE ON indicator (active indicator) illuminating when a code position is displayed. In the normal operating mode, the MODE ON display indicates secondary mode operation.Any code position which does not have a diagnostic code logged will display “– –” for both the main and Subcodes. No diagnostic codes are logged after an empty code position.

B.Clearing Active Indicators. A diagnostic code’s active indicator can be cleared, which allows the code to be removed from the code list.The active indicator clearing methods are:
1. Power down — All active indicators, except Code 69 34 (refer to the code chart), are cleared at ECU power down.
2. Self-clearing — Some codes will clear their active indicator when the condition causing the code is no longer detected by the ECU.
3. Manual — Some active indicators can be cleared manually, while in the diagnostic display mode, after the condition causing the code is corrected.

C.Manually Clearing Codes and Active Indicators from the Code List. To clear active indicators or all codes:
1. Enter the Diagnostic Display Mode.
2. Press and hold the MODE button, approximately three seconds, until a tone sounds once. All active indicators are cleared. To remove all codes, press and hold the MODE button for ten seconds until the shift selector tone sounds twice.All codes will be cleared at ECU power down.
CAUTION:If an active indicator is cleared while the transmission is locked in a forward range or reverse (fail-to-range), the transmission will remain in the forward range or reverse afterthe clearing procedure is completed. Neutral must be manually selected.

D.Exiting the Diagnostic Display Mode. Exit the diagnostic display mode using one of the following procedures:
1. On a pushbutton shift selector, press the ⇑ (Up) and ⇓ (Down) arrow buttons at the same time or press any range button, D, N, or R. The shift (D, N, or R) is commanded if not inhibited by an active code.
2. On a lever shift selector, momentarily press the DISPLAYMODE button or move the shift lever to any shift position other than the one it was in when the diagnostic display mode was activated. If the shift is inhibited, the ECU will continue to command the current range and sound the tone continuously until the lever is returned to its original position.
3. Wait until timeout (approximately 10 minutes) and the system will automatically return to the normal operating mode.
4. Turn off power to the ECU (turn off the vehicle engine at the ignition switch)

The manual can be found here:
http://ww2.justanswer.com/uploads/H...ison_transmission_md3060_trouble-shooting.pdf
The above info was copied from Section 6.

I got to know this manual inside and out when my 1994 RV gave me problems. I wound up replacing part of the transmission wiring harness, the harness was getting spurious signals in the sensor wiring.

 

[Blairg]

Thanks for all the information. I will go back down tomorrow and mess with it. I guess the odd part was the fact we couldn't clear the codes with the computer. Computer recognizes the transmission but kind of just sits their.
The adventure continues...

Blair

 

[Suprman]

I would check the entire harness. Especially where it comes out of the cab, drivers hump behind the grill. The plastic insulation gets brittle and cracks allowing wires to intermittently touch each other or ground.

 

[Blairg]

Little update...It was user error on my part not holding the mode button long enough to clear the codes from Friday. Was able to clear the original codes but they were replaced with two additional codes. Turbine speed code and a grounding fault on a solenoid. My guess is who ever installed the pan and damaged the original wiring leading to the G solenoid also damaged other wiring in the pan as well.

Blair

 

[NDT]

Have your mechanic pull the pan completely off and carefully inspect for more hidden damage.