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Thread: Shifting straight up 1-2-3-4 at WOT at less than 30 mph?

  1. #1
    Tuner in Training
    Join Date
    Feb 2019
    Posts
    14

    Shifting straight up 1-2-3-4 at WOT at less than 30 mph?

    Okay I messed up and started this in the engine tuning area,
    Most of you probably know what is causing this but a 1999 5.3L Truck.

    Just a Cam and springs, Long Tubes, Ported Heads, CAI and 3000 stall converter.

    Should be a simple tune. Dyno fine. Made 278 rwhp (I didn't do the engine)


    But when you drive it on the street and go WOT form a dead stand still or WOT at low speed it goes 1-2-3-4 gear changes and obviously goes no where (and would kill the trans if we leave it that way)


    Tune and logs are attached.


    By the way it does fine if you pull it to D1 and manually shift to D2 then D3 but goes directly to 4th. But sometimes if you go WOT it acts totally fine????? You can see in the logs, it normally shifts up and stays in high gear (going nowhere) but sometimes it shifts down and goes great.


    Anyone seen this?

    Again this is the stock trans calibration. I will change the shift points but would like to get this fixed first.
    Attached Files Attached Files

  2. #2
    Tuner
    Join Date
    Aug 2016
    Location
    Swansea Wales UK
    Posts
    177
    No expert but looking at your full throttle shift speeds, normal, performance, they look to low and the down shift speed should be less than the upshift speed