Allison transmission

[Lightningmike]

Looking for some help. I have a 2009 gmc 2500 with 6 speed Allison. I jumped in it the other day and drove it across the yard. When I went to back up it didn't want to go into gear. When it did it clunker and dug a couple little holes with tires.

Drove it a couple miles and stopped. Did same thing trying to back up. Then when I got out on road it was reving higher than normal and couldn't get over 80km. I didn't push it too hard as it seemed it wasn't shifting properly. Parked it and today I had a hard time getting into any gear. It was saying "shift inhibited, shift to neutral to reset". I did and nothing changed .
The first time it happened it was saying something about stabilitrak or stabililink.

I pulled the wiring plug on back right side and it had signs of tyranny oil in the pin holes . Cleaned and dried it out and still acts the same.

Anyone run into this?
Thanks in advance for any positive input. Lol

 

[2kDoo]

she gone it sounds like

 

[TROLLCAT]

Allison does not live here anymore

 

[Lightningmike]

she gone it sounds like

From the turn of the key? It hasn't showed any signs prior to this. To me it seems like a sensor or something. 162,000 km

 

[gedakbx]

Try disconnecting the batteries for 15mins. Then reconnect and try it again

 

[2kDoo]

From the turn of the key? It hasn't showed any signs prior to this. To me it seems like a sensor or something. 162,000 km

if you have any chip, yes

 

[TROLLCAT]

From the turn of the key? It hasn't showed any signs prior to this. To me it seems like a sensor or something. 162,000 km

needs a scan to confirm

 

[Lightningmike]

Try disconnecting the batteries for 15mins. Then reconnect and try it again

I tried that first. Sorry forgot to mention that

 

[Lightningmike]

if you have any chip, yes

Did have a little bump for fuel economy put in about 3 years ago when the particulate filter plugged up. Had it removed then too

 

[Lightningmike]

needs a scan to confirm

I will have to track down someone that can come out and do that I guess.

 

[Cableguy]

there is a seal in trany to keep oil out of the harness I had similar problema and had to change out the harness and seal on transmission
oil in there shorts across and messes up the tcm faily easy fix if you have a hoist to change it out on as it is quite common on our trucks I was told

 

[Dazzler]

My 03 will do that when I first start it up, I have to let it run a second or 3 till the altinator kicks in. If I shift before that it says shift inhibitor. I assume mine to be a bad battery or altinator.

 

[Lightningmike]

So I talked to a friend of mine who owns a transmission shop. He said it's most likely the transmission control module which is mounted on fan shroud...... easy fix right.....
WRONG!!! Same part number from 09-15 and there is none available in North America. WTF? Somebody gots to make some somewhere right. Will be doing a deep dive looking. Truck has 162000 km and is literally an ornament now.

 

[The big greasy]

So I talked to a friend of mine who owns a transmission shop. He said it's most likely the transmission control module which is mounted on fan shroud...... easy fix right.....
WRONG!!! Same part number from 09-15 and there is none available in North America. WTF? Somebody gots to make some somewhere right. Will be doing a deep dive looking. Truck has 162000 km and is literally an ornament now.

Maybe an auto wrecker somewhere would have one to try.

 

[gdhillon]

I wonder if you could rob it off a wrecked 15 with lower miles ?

 

[gdhillon]

Maybe an auto wrecker somewhere would have one to try.

Lol you beat me to it

 

[Lightningmike]

Possibly. Might be an issue with programming but not sure. Have too investigate some more

 

[sirkdev]

We did one on my brother in laws 08 I believe it needs to be programmed to yours specific. Not sure if you are deleted if there is trans tuning in it?

 

[JMCX]

My 2011 has given me the shift inhibit message a few times. Only on a cold start and only if l quickly put it in gear. Restart and it's gone.

It went into limp mode once (3rd gear only) when the output speed sensor failed. I also had no speedo when that happened.

 

[teeroy]

There is a transmission control fuse, mine popped and it would always try to start out in second gear and wouldn't shift to any higher gears. Replaced fuse and it was fine after that. Something to check anyways.