# problems with allison trans 1000 series



## mikes (Mar 11, 2004)

I have a 2002 gmc (158,000kms) with a allison 1000 series 5 speed automatic. My question is why would it shift into 3rd gear and stay when driving down the road at highway speeds. I have taken it in to 2 dealers and no answers.There is a code that comes but they say it's no help(go figure). To reset this problem i have to pull over and shut off the ignition and start it again and drive away. Also it stays in 3rd even when you are at a dead stop and try to drive away.

Should I take it to a transmission shop? Found a truck shop that repairs allison and they told me to take it to the dealer, that they only work on the bigger trucks. Does anyone know wher there might be a helpfull repair in Sarnia, Ontario Canada or close by???
please help !!!!



 :laugh:


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## C Nash (Mar 11, 2004)

problems with allison trans 1000 series

Hi Mikes,
What are the dealers telling you and what have they checked? How long have you been having the problem and how many miles on the GMC? I would think there would be some kind of code stored. Sounds like you have a sticking solinoid or sticking valve but, I am not an expert on the Allision.  there was an allision man on here that seemed to really knw them.  Maybe someone else will jump in that has experience on the allision.  I would hunt a major truck repair shop and get their opinion or call GMC.


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## Edmund A Skibinski (Mar 13, 2004)

problems with allison trans 1000 series

  mikes , I had my Allison Transmisson recalibrated at a authorized Allison Service Center last August not for what your experiencing , but any work done on your transmisson must be authorized by Allison first and then you set your appointment up with them . Don't let anyone else but a Allison techican do anything to your transmisson , not a GM techican , nobody , that's how Allison as it set-up and that's how they want it , this is what Allison told me .


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## geek (Mar 20, 2004)

problems with allison trans 1000 series

Has anyone checked your gear select position sensor.  It is mounted on the side of your transmission and looks for x amount of voltage from the gear selector.  Each gear position has a different voltage assigned to it.  This is how it was explained to me when mine went south.  My 2001 2500HD 4x4 w/ 8.1L and Allison was running fine, I parked it for about 20 mins., and when I tried to drive again it would only allow me to select park, reverse and second.  I hope this is of some help.

 quote:_Originally posted by mikes_

I have a 2002 gmc (158,000kms) with a allison 1000 series 5 speed automatic. My question is why would it shift into 3rd gear and stay when driving down the road at highway speeds. I have taken it in to 2 dealers and no answers.There is a code that comes but they say it's no help(go figure). To reset this problem i have to pull over and shut off the ignition and start it again and drive away. Also it stays in 3rd even when you are at a dead stop and try to drive away.

Should I take it to a transmission shop? Found a truck shop that repairs allison and they told me to take it to the dealer, that they only work on the bigger trucks. Does anyone know wher there might be a helpfull repair in Sarnia, Ontario Canada or close by???
please help !!!!



 :laugh:


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