Engine starts, Sounds like high idle, like torque converter not engagedPress drive or reverse nothing does not engageTry to engage drive, same for reverseIt shows 6 but it blinks and beepsDid the diagnosticNo codesJust -- for all five diagnostic modesAdded FLUID any wayNo low oil/fluid codeI do get an OL 7 0When first pushing the up down arrowsBook says this is low sump tempYeah we are parked in front of Carl's JrEngine and Trans are coolBut we drove over here with no problems, Looks like we are spending the night on a busy Blvd, in front of Carl'sDW not very happyMy process of looking for another RV, just got stepped up in priority

Sorry to hear that. Auto trannys are an odd beast; they can be fine right up to the point stop altogether. Good luck and I hope it's something cheap!

Ouch - best wishes for a speedy fix.Could be worse places to be broken down, at least you have access to ood comforting junk food while waiting for roadside to show up :)

Got goingFound some info, A post on a fleet bus website, engine speed to high, would not engage,Stuck throttle, With everything off I reached down and pulled up on the pedalThen did not touch pedal while turning the keyWas able to goto drive and moved RVWe are safely parked for the nightHope everything is ok in the morningWill be lubeing everything tomorrow staring at pedal linkageWhy no error code for this ?

I believe most allison transmissions will not engage over 1 thousand rpms so there won't be a fault code if this the case just my 2 cents good luck

hopefully that's your problem fixed. On my Duramax, it wouldn't go into gear at all. It ended up being the TCM(transmission computer module).

Stuck broke down Allison trans, solved ? Got going

11 Replies

lynndiwagon
Explorer
Feb 02, 2017
Ahhh, your sig doesn't mention the year or make of your vehicle. I don't think they used a TCM until around 2011.
MrWizard
Moderator
Feb 02, 2017
Handi

That doesn't look anything like the big metal box under my shift pad
1995 Allison works trans, 6 speed
wolfe10
Explorer
Feb 02, 2017
Yup, if engine idle speed too high, shift pad will flash, but NOT go into gear.
Tom_Barb
Explorer
Feb 02, 2017
This feature of not engaging at a higher RPM, is a safety to prevent the transmission from engaging while the PTO is operating..
lynndiwagon
Explorer
Feb 02, 2017
The Allison Transmission is mechanically practically bullet proof. I had a similar situation, with some really weird symptoms, and it ended up being the Transmission Control Module (TCM.) GM will charge about $900.00 to change this out. If you look around, on a national on line retailer (starts with the letter "A"), you can find this part for around $285.00 whereas GM will charge $700.00 for the same part. It will need to be programmed by the dealer. Might be worth having a spare one around as these are known to cause similar problems.

Here
rhagfo
Explorer III
Feb 02, 2017
MrWizard wrote:
Got going
Found some info, A post on a fleet bus website, engine speed to high, would not engage,
Stuck throttle,

With everything off I reached down and pulled up on the pedal
Then did not touch pedal while turning the key

Was able to goto drive and moved RV
We are safely parked for the night
Hope everything is ok in the morning
Will be lubeing everything tomorrow staring at pedal linkage

Why no error code for this ?

I never touch the throttle while starting, engines are electronically controlled, no need to touch.
I would be checking throttle return spring, and APPS/TPS (AKA as the electronic device that controls engine speed).
Pipeman
Explorer
Feb 02, 2017
hopefully that's your problem fixed. On my Duramax, it wouldn't go into gear at all. It ended up being the TCM(transmission computer module).
TomandCandy
Explorer
Feb 02, 2017
I believe most allison transmissions will not engage over 1 thousand rpms so there won't be a fault code if this the case just my 2 cents good luck
MrWizard
Moderator
Feb 02, 2017
Got going
Found some info, A post on a fleet bus website, engine speed to high, would not engage,
Stuck throttle,

With everything off I reached down and pulled up on the pedal
Then did not touch pedal while turning the key

Was able to goto drive and moved RV
We are safely parked for the night
Hope everything is ok in the morning
Will be lubeing everything tomorrow staring at pedal linkage

Why no error code for this ?
GordonThree
Explorer
Feb 02, 2017
Ouch - best wishes for a speedy fix.

Could be worse places to be broken down, at least you have access to ood comforting junk food while waiting for roadside to show up :)