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  1. #1

    Default what kind of transmission do i have

    I have a 2005 Silverado LS 4x4 with a 6.0 engine and auto trans. Where do I look to see if the transmission is an Allison or not

  2. #2


    You can check your RPO codes in the glove box. MT1 is the 4L80e which was the standared auto at that point for the larger engines. Another possible tranny is the 4L60e which is M30 or the 4L65e which is M32. Not sure what the Allison RPO code is.

    - - - Updated - - -

    Just found the RPO for the Allison its M74.

    1996 Chevy Tahoe LT 5.7L V8 4X4 205,000+ miles. Built proudly at Janesville Assembly in Janesville, Wisconsin
    Basic mods: Lights all over, bunch of electrical work, and a couple cooling mods.

    Check out my other mods in My Garage:

  3. #3


    The Allison trans is only available with the Dmax.

  4. #4


    Thank you. I have the MT1. I appreciate your time.

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