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Gmc Tranny

Discussion in 'Chevy Trucks' started by GMC HD, Nov 14, 2003.

  1. GMC HD

    GMC HD Junior Member
    from CT
    Messages: 10

    recently brought a gmc 2500 hd how do i find out which transmisson is in it, 8100 vortec engine. vin codes don't specify trans.

    thanx t
     
  2. plowking35

    plowking35 2000 Club Member
    from SE CT
    Messages: 2,923

    only auto tranny with the 8.1 is the allison
     
  3. GMC HD

    GMC HD Junior Member
    from CT
    Messages: 10

    i thought so but some was telling me different. iwanted to make sure..

    thanx
     
  4. ratlover

    ratlover PlowSite.com Addict
    from IL
    Messages: 1,325

    I thought you could get a 4l80e with the 8.1:confused:

    Its easy to tell the difference between a 4l80e and a Allison without even getting under the truck or searching for codes. The allison is a 5 speed and the 4l80e is a 4 speed. Just dont get confused and count the torque converter locking up as a gear change.
     
  5. Crazy_Eddie

    Crazy_Eddie Member
    Messages: 38

    Look in your glovebox for one of the following codes...

    M74 Transmission, Allison 1000 5-speed automatic
    ML6 Transmission, 6-speed manual, heavy-duty
    MT1 Transmission, 4-speed automatic, heavy-duty
    MW3 Transmission, 5-speed manual

    They are listed in alphabetical order...
     
  6. GMC HD

    GMC HD Junior Member
    from CT
    Messages: 10

    Thanx for the input guys i've got down now... m74:waving: