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Thread: Help with LT4 engine swap in 2014 Silverado LTZ 2WD 6.2L

  1. #1

    Help with LT4 engine swap in 2014 Silverado LTZ 2WD 6.2L

    I replaced the stock 6.2L engine with a Chevy Performance LT4 crate engine. Kept the original ECU, wiring harness, 6L80E transmission, and TCM. Transmission rebuilt for 900hp and flashed TCM, and all other moving parts upgraded. My engine tuner didn't have any trouble with engine tune but we're pulling our hair out trying to get it to shift dependably. If I drive it like a little old lady there's no problem but from 50% to WOT it does strange things. May skip shift up or down, or may go thru 1st and 2nd, then search for a gear. We've tried adjusting TPS, torque settings, RPM shift points, etc. but not getting good results. We haven't found anybody else who has put this engine in a newer vehicle. Most people use manual transmissions or older automatics that don't require electronics so we're looking for somebody with experience in direct injection engines and 6L80 transmissions.

  2. #2
    Tuner Camaro6's Avatar
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    Do you have a tune to upload and log showing the issue? I would guess that the tune has the pedal and tq tables changed which is freaking the trans out on tq numbers and making it shift out of the ordinary. This is true no matter the trans bolted to the LT1 or 4.
    2018 Camaro SS, LT4 Fuel System, LT4 S/C

  3. #3

    Current tune

    Quote Originally Posted by Camaro6 View Post
    Do you have a tune to upload and log showing the issue? I would guess that the tune has the pedal and tq tables changed which is freaking the trans out on tq numbers and making it shift out of the ordinary. This is true no matter the trans bolted to the LT1 or 4.
    Are you asking to see my current tune? If so I would have to ask my tuner for a copy of the last version uploaded to my truck.

  4. #4
    Senior Tuner Ben Charles's Avatar
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    I bet it’s a Kw to axle Tq problem

    Email Tunes, Bencharles_10@hotmail.com
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  5. #5
    Tuner in Training
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    Bluecat transmission table generator