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Thread: can someone please help me with my trans tune

  1. #1
    Tuner in Training
    Join Date
    Apr 2017
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    17

    can someone please help me with my trans tune

    hi I was wondering if anyone can help me or look a my trans tune and let me know what I'm doing wrong. I've tried everything now. its like the engine to fast for the computer or something.
    going though the gears normally the trans will shift fine the moment its at wot and down shifts its like it drops out of gear and there's nothing there till we let off the throttle then go wot again and its fine and pulls good. sometimes from a dead stop we go wot and it shifts fine then sometimes it will hit the limiter and wont shift till we let off the throttle. its getting supper annoying and any advice would be appreciated.
    the trucks an 07.5 Silverado he put an ls2 with stage 4 btr truck cam heads are milled .35 and 3200 stall stock 4l60 also change the 3.42 to 3.73
    mick LS2 STAGE 4 BTR RUCK CAM tune bluecats trans tabe change.hpt

  2. #2
    Tuner
    Join Date
    May 2006
    Location
    Baton Rouge, LA
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    84
    Quote Originally Posted by fbodyraing1 View Post
    hi I was wondering if anyone can help me or look a my trans tune and let me know what I'm doing wrong. I've tried everything now. its like the engine to fast for the computer or something.
    going though the gears normally the trans will shift fine the moment its at wot and down shifts its like it drops out of gear and there's nothing there till we let off the throttle then go wot again and its fine and pulls good. sometimes from a dead stop we go wot and it shifts fine then sometimes it will hit the limiter and wont shift till we let off the throttle. its getting supper annoying and any advice would be appreciated.
    the trucks an 07.5 Silverado he put an ls2 with stage 4 btr truck cam heads are milled .35 and 3200 stall stock 4l60 also change the 3.42 to 3.73
    mick LS2 STAGE 4 BTR RUCK CAM tune bluecats trans tabe change.hpt
    Looking at your file, I'm curious as to why your WOT shift speed settings are high for the 1->2 and 2->3 shifts. If you changed the rear from 3.42 to 3.73, then you want to tune for that change. Based on your description of the "issue", your settings are somewhat out of range for a 4L6xE trans with 3.73:1 final drive ratio. Lower your WOT speed settings to:

    1->2: 25
    2->3: 50
    3->4: 140
    2->1: 20
    3->2: 40
    4->3: 130

    Start with the above, and adjust (lower) as needed. I would match the "Normal (Part Throttle)" shift table's "100% TPS" column to match that of your updated (lower) WOT Shift Speed table. Then interpolate between horizontal bounds. WOT Enable/Disable settings are your choice. Recommend the shift RPM be set to wherever that engine makes it's peak hp (on its power curve). No sense in over-revving, ASSUMING peak power is lower than current settings.
    Last edited by 1badc10; 06-20-2020 at 06:40 PM.
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