Allison Keypad Dead

[Misterpickels69]

I bought a 2008 International RE Maxxforce DT466 and drove it up to the Yukon from BC with no issues except a speedometer that only worked periodically and at one point we got stuck in third gear and couldn't shift up or down for a few minutes.

Bought new batteries for it, and now the Allison keypad (automatic transmission 3000) won't light up. Also, the bus won't start if a certain cable in the battery tray is connected. It will start just fine if this cable is disconnected. I'm thinking that this cable has something to do with the Transmission Control Unit and that there's some safety on it that won't allow you to start the bus if the TCU is fried? Is the TCU also responsible for the speedometer malfunction?

Does this sound reasonable? Is this a problem I can fix on my own, having no mechanical experience? If anyone has a driver's manual for this bus or a pinout for an Allision 3000 transmission, please send me the link! :Thanx:

 

[turf]

when something doenst work after i change something..... usually what i did was the problem.

i suspect you installed the new battery incorrectly.

 

[ewo1]

Allison 3000 diagnostic manual

file is over 9mb, too large to upload here.

Link -> https://s6dc2dc82dd3d959c.jimconten...nsmission TS3989EN Troubleshooting Manual.pdf

In order for your bus to start it requires 2 things (electrically), good working ECU and TCM.

There should be 2 extra 10-12 ga wires in the battery box that should have inline fuse holders connected to the + terminals of the battery. One fuse is for the ECU and the other is for the TCM.

The fact that you say she starts is confusing because both units work hand in hand in order to start the bus.

I believe you need to make two more posts b4 you can upload pics, but pics of the battery wires would be helpful.

The fact that the pushpad does not light up after the new batteries tells me that either you connected it wrong or the fuse blew.

If your pushpad is dark, not lighting up, then you need to verify that TCM fuse is still good.

 

[ewo1]

.... and at one point we got stuck in third gear and couldn't shift up or down for a few minutes.

This is possibly a secondary issue to your first issue, electrical connection integrity.

The TCM has a feature called "Limp Mode" which will put the tranny into third gear and not shift when it detects a problem. This is so you can get the unit off the road and to a safe place.

The fact that it did that and went away coupled with your other issue makes me want to believe that if you fix the first issue then this second issue just might go away.

Connection integrity is important, loose, rusted or simply worn out connection can cause havoc on these units. Find your grounds, check and re-clean if necessary, same with your power connections.

 

[sportyrick]

cause and effect, you changed something when u changed batteries, didn't pay attention!!!!!! Take everything out of battery box and start over....check everything for cleanliness and proper orientation. You are probably hooking up that wire to wrong polarity.

 

[shortbus4x4]

Has already said check the clean power and grounds at the batteries. Probably 3 fuses, one for ECM, one for IDM and one for TCM. The TCM fuse should be a 10 amp while the other two are 40 amp fuses. Check the connections too on the fuses and plugs on your clean power/ground harness.

The TCM should be near the trans on the inside of the frame rail. If it's a fourth gen TCM which it probably is it will have a porcupine heat sink. These like to fail alot, the fix is to replace it with a 5th gen TCM. You really need a laptop with Allison DOC or other program to diagnose properly though. The TCM connector is an 80 pin connector. Pin 63 is ignition voltage, pins 9,10, 69, and 70 are the battery power and grounds. I can't remember which is which but two are power and two are ground. If any of those don't have power or ground your TCM won't fire up and tell the ECM that the trans is in neutral which means no starter engagement.

 

[Misterpickels69]

Do it myself ?

Do you think its something I can do myself ? Change the tcm and reprogram it with a normal laptop ? How hard it is ? Im handy but in carpentry, not in light heavy duty diesel mechanic ! All 3 fuses are fine and I test them all , my assumption is the tcm is fried its the only thing that will stop me from starting my bus because when the white wire sticking out of the black cable on the negative side of the battery is unplugged the bus start but if its plug in it doesnt start at all and if I do start it and plug that wire back on after its started the check transmission light is on , at the front dash and no light at all in the push pad allison transmission so I think the tcm is fried !

 

[shortbus4x4]

Do you think its something I can do myself ? Change the tcm and reprogram it with a normal laptop ? How hard it is ? Im handy but in carpentry, not in light heavy duty diesel mechanic ! All 3 fuses are fine and I test them all , my assumption is the tcm is fried its the only thing that will stop me from starting my bus because when the white wire sticking out of the black cable on the negative side of the battery is unplugged the bus start but if its plug in it doesnt start at all and if I do start it and plug that wire back on after its started the check transmission light is on , at the front dash and no light at all in the push pad allison transmission so I think the tcm is fried !

Make sure you check ignition and battery power and ground at the TCM, it could be a wiring issue. When I diagnose a bad TCM I always check for communication with it with my laptop. If no communication then I check the clean power and grounds at the battery because they're easy to check. After that I check the TCM connector. Make sure you're using a test light that draws a few amps as I've seen issues more than once where my DVOM says it has 12 volts but there isn't enough amps due to wiring issues.

You will need Allison reflash access to program a replacement TCM. But you can pull the old TCM to get numbers off of it and also get the trans S/N. Any Allison dealer should be able to bench program a replacement TCM for you and then you can install it.

 

[ewo1]

If your push pad is dead, wont light up, bus will not start.
On my older bus, 1999 amtran, i had the same problem,

Here is the thread on it, maybe it will help…

https://www.skoolie.net/forums/f33/md3060-dead-dark-shift-panel-24837.html

A common problem is a broken wire within the harness, usually somewhere near the tranny.

You will have to tone out the wires to check for wire integrity.

Not hard to do once you understand how the system works.

 

[ewo1]

Do you think its something I can do myself ? Change the tcm and reprogram it with a normal laptop ? How hard it is ? Im handy but in carpentry, not in light heavy duty diesel mechanic ! All 3 fuses are fine and I test them all , my assumption is the tcm is fried its the only thing that will stop me from starting my bus because when the white wire sticking out of the black cable on the negative side of the battery is unplugged the bus start but if its plug in it doesnt start at all and if I do start it and plug that wire back on after its started the check transmission light is on , at the front dash and no light at all in the push pad allison transmission so I think the tcm is fried !

So if our check trans light comes on that leads me to believe the TCM may not be totally dead.
The signal for that light comes from the TCM so at some degree, the TCM is talking.

No light on the pushpad...the TCM sends a voltage to the pushpad to power it up. If that voltage is not reaching the pushpad, it will not light up and the bus will not start.

If the pushpad voltage wire is broken and intermittent, that could be a possible cause why it went into limp mode.

To answer one of your questions, unless you have allison doc then NO you cannot simply reflash the TCM and besides, you would need an image file in order to do that anyway.

I gave you a link to the Allison manual. Did you download it and look for the pinouts?

 

[Mat7783]

Wow

Interesting.the in-line fuse connected to the positive battery lead is a 30amp.my TCM is a WTEC3 version.so you are sure that it only requires 10amp fuse?

 

[ewo1]

Interesting.the in-line fuse connected to the positive battery lead is a 30amp.my TCM is a WTEC3 version.so you are sure that it only requires 10amp fuse?

Yes, 10 amps.
Replace it, go for a 10 mile drive, pull over and touch fuse holder to see if it is getting warm/hot.

This is the very first troubleshooting step.

Also, more good info with diagrams..->> https://www.skoolie.net/forums/f49/...-but-no-light-to-digital-shifter-28362-2.html

 

[nikitis]

If you put a 10 AMP in there it will only blow the fuse if 10 AMP isn't sufficient, no harm done. And you'll know for sure. If it works with 10 AMP fuses then it likely uses less than 10 AMP's and is safe to use 10 AMP's, if you insert 10 AMP's and it continues to blow then you are using more than 10 AMP's at a times.

Whether this is legitimate and it needs more than 10 AMPS at times by design, then it probably is a 30 AMP fuse that is required.

If it is supposed to use 10 AMP's and it blows, then you could have bad wiring in line somewhere or something else tied into the power line feeding additional Amperage through it which would be bad for the electroonics on the TCM.

If you find 10 AMP's are blowing regullarly, you'll want to trace the lines and ensure it's the only device on that line, and if so then maybe it does require a 30 AMP. If it isn't the only device on that line, rewire it so that it is the only device on the line, and try again with 10 AMP Fuse.

This is pretty much Fuse sizing 101 in electrical, and can apply to any device testing when you don't know the fuse size for things.