LQ9 2WD Trans behind LQ4 w/AWD PCM LS SWAP’d ‘89 Caprice

Trying to save the world without buying a new transmission [4L65E]. LQ4 is stock. I have both the 2005 Escalade LQ9 and 2004 Cadillac EXT LQ4 harnesses, but only the ‘04 EXT PCM. Intend to drive by wire and run E85. All insight is appreciated. Thanks!

I'm pretty sure the 2004 Escalade EXT PCM will work with either harness and the 4L65E. Have you read the bin from the PCM already? Are you looking to only use E85 or do a flex fuel conversion? Is this a retrofit application?

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Originally Posted by Pulse_GTO

I'm pretty sure the 2004 Escalade EXT PCM will work with either harness and the 4L65E. Have you read the bin from the PCM already? Are you looking to only use E85 or do a flex fuel conversion? Is this a retrofit application?

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Thanks for prompt response! Yes it is retro fitted. Installed in a 1989 caprice. And no I have not read bin file nor generated XDF. (Forgive any improper terminology) just trying to stay ahead of build issues that may arise. Must acquire the “OBD LX” and build “bench harness” before proceeding. I’m wanted to use E85 for gas costs but really would love to get this thing running on water…lol. Type of petro doesn’t matter. Can’t wait to wake the beast.

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Originally Posted by blakxavier307

Thanks for prompt response! Yes it is retro fitted. Installed in a 1989 caprice. And no I have not read bin file nor generated XDF. (Forgive any improper terminology) just trying to stay ahead of build issues that may arise. Must acquire the “OBD LX” and build “bench harness” before proceeding. I’m wanted to use E85 for gas costs but really would love to get this thing running on water…lol. Type of petro doesn’t matter. Can’t wait to wake the beast.

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I would probably install a flex fuel sensor that way you could use whatever blend of gas that is available.