Allison 5sp: Problem downshift out of OD

[05chevy]

I have a LLY that Im having problems with when it shift to OD. If you try and go WOT say 45-60 it will not kick down to 4th gear. Once under 45 it will down shift. You can lock out OD fine. I can also manually down shift into 3rd with no problem. I tried another stock tune from another LLY and it still does the same thing.

Truck has a new throttle pedal in it due to a mice nest in the fuse box but all wires have been repaired.

Could it be something internally in the trans that is not letting it down shift?. Truck has no codes or pending codes.

Thanks for any help

 

[Mike L.]

Trans cannot do that. Might need to reset the throttle sensor.

 

[05chevy]

Can i do that with efi live or will i need a tech 2?

 

[Mike L.]

Can i do that with efi live or will i need a tech 2?

Don't think EFI can do it.

 

[05chevy]

My local GM dealer said the throttle sensor doesnt need to be reset. And they said they have no clue what could be wrong.

 

[the freeze]

Log your throttle position if it goes to 100% then I would think it tO be fine????

 

[05chevy]

It will go to 100% already logged that. Something is not telling the trans to downshift at WOT at 45-60mph. It should downshift to 3rd at 45mph. All it does is lug its self until the turbo starts to light.

 

[juddski88]

Maybe try an 01 tcm file?

 

[05chevy]

Maybe try an 01 tcm file?

Know where I can get one

 

[Mike L.]

They work realy well except you will lose O/D cancell.

 

[ncarolina23e]

same problem

 

[05chevy]

Do you think a faulty speed sensor could be a problem? The speedo needle doesnt move smooth. Kind if jumps. Just throwing that out there.

 

[Chevy1925]

Do you think a faulty speed sensor could be a problem? The speedo needle doesnt move smooth. Kind if jumps. Just throwing that out there.

monitor your MPH on a log and see if it moves smooth

 

[JMK777]

Is the only reason the 01 tcm tune good because its a slow learner or is there more to it?

 

[juddski88]

They work realy well except you will lose O/D cancell.

tapshifter

 

[Devon]

I also noticed I have the same issue. Anything about 50-60 when you lay the pedal all the way to the floor it just spools up and pulls in that gear(5th) won't downshift to 4th. I have a 01 tcm file too. Weird?


Sent from my iPhone using Tapatalk

 

[juddski88]

It unlocked fine for me Devon during the test drives. Thats the exact file that Ben built for his truck. Unlocks the converter and upshifts fine in his too

 

[Devon]

I'm talking about downshifting. Say I'm cruising down the highway going 65 in 5th gear it won't downshift to 4th when I push the pedal all the way down. Unless I slow down enough where it's forced to.


Sent from my iPhone using Tapatalk

 

[juddski88]

I call that an upshift...:rofl:

 

[GMC04DURAMAX]

Down in numbers = down shift in my book lol 5th to 4th:roflmao: