What trans do I have

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by kelo4u2, Sep 23, 2013.

  1. kelo4u2

    kelo4u2 New Member

    New here, So Hi all.
    I have a 2001 2500 Sub LT 4x4 with 8.1 l engine. How do I tell what trans I have. I'm just wondering because what everyone says about Allison trans. also how haed is it to put a leveling kit on. My back is shot (5 surgeries on my back) so I dont want to start it and not be able to finish. Thanks

    99'HEARTBEAT MODERATOR Staff Member 5+ Years ROTM Winner 1000 Posts Platinum Contributor

    To know for sure what Transmission your 2001" has and/or came with.....look inside your Glove Box, and there you will see a White Tag, and that is the Service Parts I.D.Tag, on it is your Suburbans Vin#, and a Series of Letters and Number's, those are RPO Codes, which stands for Regular Production Option, in short what the Suburban came with from the Factory,

    ***The RPO Code you would be looking for is.....MT1 which is the....4L80E, or RPO M74 which is the Allison Transmission, IIRC The Allison was not available in the 8.1 Suburbans??

    If you go the link below, and enter your Suburbans Vin#....it will show you everything the Suburban came from the Factory.


    Last edited: Oct 18, 2013
  3. RayVoy

    RayVoy Epic Member 5+ Years 5000 Posts

    Or, the 4L85E, RPO MN8

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