Results 1 to 8 of 8

Thread: 2008 GMC Sierra trans question

  1. #1
    Member Spindoctor's Avatar
    Join Date
    Jun 2007
    Posts
    57

    Default 2008 GMC Sierra trans question

    Sorry about the lack of specific RPO info on this post.
    VIN# 3GEK13Y18G258767
    This is a 2008 GMC Sierra 1500 4x4 with the 6.0ltr 15000 miles and a trans that I am not sure of as to the model. The vehicle was in 6 weeks ago for Dyno diagnostics.
    It has a very hard 1-2 up shift and a shudder under moderate load when going from 3 to 4.
    The dealer said they did not or could not feel anything wrong.
    When I tried to look at the system with my version 7.4 I could tell the data and PID stream were corrupt (Wrong info on wrong lines eg 15,000+
    rpm at idle). The ECM looked to be an E-38.
    So what I need to know is weather or not a newer version 7.5 or 8 would correct my data logging issues or is this a system that EFI Live has not yet worked out.
    The owner wants the data logs of trans pressures etc. so he can force the dealer to correct the problem or go Lemon Law on them. It is one of those vibrations that you don't notice at first but, once you do it always bugs you.
    For comparison his brother (or cousin) has the same truck and it has neither
    issue.
    As always- Thanks in advance- Tim H
    Thanks in advance- The Spindoctor (Tim H)
    Back ground-Mustang AWD500 Dyno- Over 500 tunes on systems including: Autronic, MoTec, AEM,COBB,Haltec, Electromotive,Greddy, Microtech (to name just a few)and now EFI Live!

  2. #2
    Lifetime Member GMPX's Avatar
    Join Date
    Apr 2003
    Posts
    13,148

    Default

    In the latest update there was a number of trans PID's added for the 6 speed (assuming that is what this trans is?). You will certainly need to update from 7.4.

    You will need to update to 7.5, you can find the download link HERE

    Update your EFILive system to build V7.5.5 build 82 by installing V7.5.5 Build 72 (which is what is in the download link) and selecting the Windows Start menu option:
    Start->All Programs->EFILive->V8->Tools->Check for New Updates.

    Cheers,
    Ross
    I no longer monitor the forum, please either post your question or create a support ticket.

  3. #3
    Lifetime Member Tre-Cool's Avatar
    Join Date
    Feb 2006
    Posts
    937

    Default

    or run the v7.5 update program.

    v8 did nothing for me. updating 7.5 now though.

  4. #4
    Lifetime Member GMPX's Avatar
    Join Date
    Apr 2003
    Posts
    13,148

    Default

    Oh sorry, I put the wrong instructions up there, V8 is currently only used for managing firmware and files on the V2 hardware.

    Cheers,
    Ross
    I no longer monitor the forum, please either post your question or create a support ticket.

  5. #5
    Lifetime Member MN C5's Avatar
    Join Date
    Mar 2005
    Posts
    376

    Default

    I didn't think the 6sp was available in a chevy until 09. At least I never found a 2008 OS for a 6sp VMax and was told by several service guys that the 6sp wasn't available until 09 in a Silverado.

  6. #6
    Lifetime Member
    Join Date
    Dec 2007
    Posts
    1,143

    Default

    GM info says it should be a 6L90E A6, if it is an LY6 6L gas engine. If it is an L76 6L gas engine, it should be a 4L70.

    Most likely the L76 in the 1500.

    The VIN looks to be incorrect too.

  7. #7
    Lifetime Member
    Join Date
    Jan 2004
    Posts
    232

    Default

    Quote Originally Posted by MN C5 View Post
    I didn't think the 6sp was available in a chevy until 09. At least I never found a 2008 OS for a 6sp VMax and was told by several service guys that the 6sp wasn't available until 09 in a Silverado.
    He said Sierra, could be a Denali right?

  8. #8
    Lifetime Member MN C5's Avatar
    Join Date
    Mar 2005
    Posts
    376

    Default

    Quote Originally Posted by XLR8NSS View Post
    He said Sierra, could be a Denali right?
    The Denali has the 6.2 though right?

Similar Threads

  1. Late 2007 - Early 2008 Silverado 6.0 SD Tune Question
    By Mike Norris in forum E37, E38 & E67 PFI ECM's
    Replies: 9
    Last Post: March 9th, 2010, 06:57 PM
  2. sierra 2008, AFR doesn't stay constant @ wot
    By odd boy in forum E37, E38 & E67 PFI ECM's
    Replies: 14
    Last Post: March 5th, 2009, 02:50 PM
  3. support for 2008 GMC Sierra V6 2wd
    By camcojb in forum E37, E38 & E67 PFI ECM's
    Replies: 2
    Last Post: October 28th, 2008, 02:29 PM
  4. Trans swap - GenIV pcm T42 question
    By 350SS in forum 4speed RWD/FWD Transmission Tuning (incl T42)
    Replies: 0
    Last Post: October 24th, 2008, 05:36 PM
  5. Question about A4 trans temp sensor for LS1 F-body
    By Joel_SS in forum 4speed RWD/FWD Transmission Tuning (incl T42)
    Replies: 13
    Last Post: August 24th, 2006, 04:18 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •