Results 1 to 2 of 2

Thread: 09 Express 4L85e to Allison

  1. #1
    New Member
    Join Date
    Apr 2021

    Default 09 Express 4L85e to Allison

    Forgive me if I am in the wrong section.
    I am wanting to swap a 4L85e for a Allison 1000.
    My express is an 09 model LMM.
    I can manage the wiring changes, but as far as programming goes would I need to switch the van to a truck OS and is it compatible to switch these OS's?
    Which TCM would I need, T42A?
    Any insight or a brief run down before I go all in from someone more experienced on these. I do tons of gas conversions, but the diesel compatibility is all new to me. Can anyone give me some recommendations or anything you think I would run into doing this swap. Thank you

  2. #2
    Join Date
    Jan 2006


    Hi, you want to have a pickup powertrain in the van, so I guess the wiring , tcm, ecm cal. should be the same as a pickup
    I always thought that the Allison can't fit on a van because the floor pan doesn't allow enough space ?

Similar Threads

  1. flashing 6spd allison os into 5spd allison tcm
    By Scarface in forum Allison 5 & 6 Speed
    Replies: 8
    Last Post: April 27th, 2017, 01:52 AM
  2. 4L85E TCC Tuning Help
    By jlane330 in forum 4speed RWD/FWD Transmission Tuning (incl T42)
    Replies: 20
    Last Post: September 7th, 2016, 03:23 AM
  3. 4l85e in a duramax van
    By johnj in forum 4speed RWD/FWD Transmission Tuning (incl T42)
    Replies: 2
    Last Post: March 20th, 2013, 11:34 AM
  4. new tune for my 07 Chevy Express
    By Wolfie in forum 4speed RWD/FWD Transmission Tuning (incl T42)
    Replies: 1
    Last Post: July 30th, 2011, 04:11 AM
  5. Express Van with no PE, how bout that!
    By Wolfie in forum Gen III V8 Specific
    Replies: 2
    Last Post: May 16th, 2010, 09:28 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