Allison 3000 Shift Pad Dead—No Start After TCM Replacement on 2007 International

[701 DZL]

I have a 2007 international with a allison 3000 transmission, the other morning I went out to start it and the shift indicator was flashing from nutural to the cat eyes, when it was doing that the transmission was actually attempting to go into gear and turn the drive shaft. Was able to drive to the shop, checked everything underneath it all looked good, started the bus again to back it out, started and then the shift pad went black. Pulled the tcm off and took it to a dealer to have it tested, they couldn't pull anything off of it and I couldn't hook up to it with my computer either. They sold me a new one put it on and I Still don't have a shift indicator and the bus wont start, if I jump the starter solinoid it starts so I know everything on that end is good. Did my shifter short out which fried my tcm or am I missing something

 

[Omnibot2000]

Need wiring schematic and start pinning out the harness.

I have had the same issue in the past on an old Sterling truck. Shift pad blank. Ended up the truck was tested in the past and someone stab tested wiring insulation and had a ton of corroded wires. Got it repaired and the shift pad lit up and worked

However. Step one. Check fuses. Our International trucks have fuses in the battery box for the TCM. First place to start.

 

[701 DZL]

Checked all the connections everything is good, the tcm was fried so o was just wondering if it fried something else or something fried it

 

[desrtdog]

@ewo1 can definitely help here… he has extensive troubleshooting creds and has been through a similar (iirc) issue with his push pad…

 

[ewo1]

I have a 2007 international with a allison 3000 transmission, the other morning I went out to start it and the shift indicator was flashing from nutural to the cat eyes, when it was doing that the transmission was actually attempting to go into gear and turn the drive shaft. Was able to drive to the shop, checked everything underneath it all looked good, started the bus again to back it out, started and then the shift pad went black. Pulled the tcm off and took it to a dealer to have it tested, they couldn't pull anything off of it and I couldn't hook up to it with my computer either. They sold me a new one put it on and I Still don't have a shift indicator and the bus wont start, if I jump the starter solinoid it starts so I know everything on that end is good. Did my shifter short out which fried my tcm or am I missing something

If the TCM is not communicating to the ECM, bus WILL NOT start. In part, it is because the NSBU is wired thru the TCM and if the ECM does not se the bus in neutral, no start.

It starts when you jump the solenoid simply because you bypassed the NSBU function.

you said you checked all the connections.... a visible check IS NO ENOUGH!
You MUST DO a physical, not visible, check!

First place to start, the TCM fuse. If your fuse is in the BAT box, pull the fuse and look at the legs. Is one of the legs darker than the other?
Look at the fuse holder/terminal iside the inline fuse holder, same question...is one darker then the other?

If so, cut out the fuse holder and replace!
Physically check your TCM ground. This means locating the ground lug, opening it up, clean...shiny clean and reattach. this is the only valid way to check it, simply looking at it is not enough!

Once you do this, I can help you more, get in much deeper but, you got to get dirty first!

check your power and ground is ALWAYs step #1!

In the mean time, do yourself a solid and get edumecated... lot's of info here!

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www.skoolie.net

Allison 3000 push pad dead - no start - repair tips

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[ewo1]

Here is the very basic/simplified power wiring scheme between the tCM and ECm.

very basic, just so you understand what you are looking at.

Your battery ground that needs to be "checked", left frame rail.
Follow the ground wire from the battery.

 

[ewo1]

allison 4th gen wiring schematic - yours should be a 4th gen.

 

[Omnibot2000]

Checked all the connections everything is good, the tcm was fried so o was just wondering if it fried something else or something fried it

Yes. If something failed and burnt the original TCM, then plugging in the 2nd TCM could be fried again.

I 2nd EWO1 and stand behind what he said here.

You really need to pin out wiring harnesses, checking for powers at the appropriate pins; grounds at the appropriate pins and further to that, look for system power on pins where it should NOT be.

Start at basics and double, triple check your works. I even write my findings on paper as to what each connector pin ohms out at, voltage is and grounds are at.

A few examples, Just recently I lost reverse on a off road vehicle. I ohm the shift solenoid. Ohm out harness to TCM. Confirm checks and TCM failed. Quick check to make sure I have no voltages in places it should not be is performed. It's good to check because I saw someone install multiple IDM's on our T444e/ Powerstroke and kept burning out multiple IDM's to find the valve cover gasket burnt/shorted out and the glow plug power feed sent system voltage up the ground injector wires after testing.

Sorry, way off topic from your current situation but just trying to give some insite on the importance of checking the electrical first.

 

[ewo1]

A few examples, Just recently I lost reverse on a off road vehicle. I ohm the shift solenoid. Ohm out harness to TCM. Confirm checks and TCM failed. Quick check to make sure I have no voltages in places it should not be is performed. It's good to check because I saw someone install multiple IDM's on our T444e/ Powerstroke and kept burning out multiple IDM's to find the valve cover gasket burnt/shorted out and the glow plug power feed sent system voltage up the ground injector wires after testing.

Sorry, way off topic from your current situation but just trying to give some insite on the importance of checking the electrical first.

Your not off topic here...you just went to the next page that's all.
The Allison manual has a very thorough section on ohm'ng out the harness. It is the next step towards troubleshooting the system.

My two issues were broken wires at the connector that goes into the transmission, rotted out pins! And they are supposed to be watertight connectors...yeah... And I figured it out by Ohm'ng the harness!

The Op stated that after installing the new TCM the Push pad went dark. classic loss of power to the Push pad, not necessarily to the TCM but that must be checked first in order to go to step 2.

I honestly don't think his TCM was even bad, the shop failed to test the bus wiring?
they sold him a new one and that one won't work too?

I wonder how much that cost?
TCM from a dealer???

I wonder if they even programmed it to recognize the architecture/build of the bus. This is why you need the CIN. No mention of reprogramming the new TCM.
If the TCM is not programmed with the correct CIN then bus may or may not start and if it does, may act out with with weird shifts or not shift at all!

I swapped the TCM in my 9906 bus (1999) with a TCM from a like engine/tranny (2005) bus and it would not let the bus go into gear because the '05 CIN was programmed for a wheelchair interlock and my '99 bus had no wheel chair to begin with.
this fix was a simple jumping of 2 wires at the TCM itself.
REEASON-2 different but similar CIN's.

Getting involved with these busses, if your not gonna spend the time and energy to first learn, then you better have deep pockets. This i see is one of the reasons people fail and give up on their builds. You gotta be willing to learn folks!

 

[701 DZL]

There was 4.8 volts pulsing in and out in pin 10 and pin 80, went through the whole harness didnt find a bad spot in the wires ran a new fused circuit it works like a charm now

 

[ewo1]

There was 4.8 volts pulsing in and out in pin 10 and pin 80, went through the whole harness didnt find a bad spot in the wires ran a new fused circuit it works like a charm now

This is awesome!
But... you said nothing wrong or did not find a bad spot...yes there is a bad spot but like you said, you didn't find it.
running a new wire was a good choice but...take the time out and figure out where it went wrong/bad. You may or may not have a future issue growing here....

Great job in fixing it though!

 

[ewo1]

There was 4.8 volts pulsing in and out in pin 10 and pin 80, went through the whole harness didnt find a bad spot in the wires ran a new fused circuit it works like a charm now

I took a look at the pinout for the gen 4 tcm, pins 10 and 80...
Pin 80 is for your speed sensor input, has nothing to do with the pushpad "lighting" up.
There is no purpose with checking for voltage at pin 80.
Pin 10, yes, it is your fused input.

Question, when you tested for voltage, what did you use as your ground source, frame of bus or pins 39 or #69 ?

You rewired pin 10, (power source) it is easy to check if the wire itself is compromised, if your willing to go the extra step...

 

[Omnibot2000]

Wow. Glad it's working.

I have to agree EWO1. I think a TCM was sold for no reason at all .

Also agree with locating the fault. To many times I have seen loss of power to locate a chaffed wire harness to find multiple other wires half worn through and barely hanging on.