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Thread: 8L90 slow shift into reverse/drive in cold start

  1. #1
    Potential Tuner
    Join Date
    Mar 2019
    Posts
    5

    8L90 slow shift into reverse/drive on cold start

    Like the title says trans is slow going into R/D but only when it's cold. After it heats up fully it acts normal. TCM is unlocked but I'm not sure if it's tune related. Any thoughts on what could be causing the issue?
    Last edited by #1GraySS; 05-30-2020 at 04:56 PM.

  2. #2
    Tuner
    Join Date
    May 2006
    Location
    Baton Rouge, LA
    Posts
    84
    Noticed my '15 Yukon Denali does that. It's almost as if the fluid flows way too slow, with insufficient fluid pressure. I've just got in the habit of using remote start to get things flowing, before I hop in & go.
    **Capt. Ron - 7th Dist. Fire**

  3. #3
    Potential Tuner
    Join Date
    Mar 2019
    Posts
    5
    I got it fixed. Just used the fast learn function in hp tuners problem solved. No more clunking in to gear and smoother shifts.