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Thread: 4L80e swap, won't shift 1>2 WOT

  1. #1
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    Default 4L80e swap, won't shift 1>2 WOT

    Ok first off it's an 04 Silverado 1500, I'm using EFILIVE with custom OS 2, and of course I did the 4L80e segment swap. We've done many other 4L80e swaps and never had this problem before. The only thing I did different is not wire in the front input speed sensor, but I did turn all the DTC processing enablers off for it and disabled all the slip test stuff too. Shouldn't this work? It drives around just fine at all part throttle driving and the 2>3 WOT works fine too???? Also this trans was taken from my '89 turbo LS swapped truck and worked fine in there....
    -John

    1991 RCSB 2WD Sierra LQ4 swap, 220/224 112 cam, Twin VSR 6766 turbos
    4L80e w/shift kit, PY 3600, and 3.73 gears.
    22 PSI and E85, 4300# with driver. 9.7@138, 1.47 sixty
    :drivin:

  2. #2
    Joe (Moderator) joecar's Avatar
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    Make sure the 2->1 WOT MPH is lower than the 1->2 WOT MPH.

  3. #3
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    Yup its set at 19mph on the wot and part throttle tables
    -John

    1991 RCSB 2WD Sierra LQ4 swap, 220/224 112 cam, Twin VSR 6766 turbos
    4L80e w/shift kit, PY 3600, and 3.73 gears.
    22 PSI and E85, 4300# with driver. 9.7@138, 1.47 sixty
    :drivin:

  4. #4
    Joe (Moderator) joecar's Avatar
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    Lower the 1->2 WOT MPH (and make sure to keep the 2->1 WOT MPH lower than it), and lower the 1->2 WOT RPM until you see the shift...

  5. #5
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    Stupid little things first:
    Did you change the ratios?
    Did you adjust the shift points?
    Did you use the A4 trans spreadsheet to make sure the upshift/downshift tables don't cross? (Ive found this makes or breaks a trans tune.)

    If you can, post the tune so we can check it out. If not, feel free to email it to me: <my username> @gmail.com.
    ~Erik~
    2013 Sonic RS Manual - 1.4L I4T E78, tuned, turbo mods, etc.
    2008 TrailBlazer SS 3SS AWD Summit White - LS2 E67/T42, bolt ons, suspension, etc.
    2002 Chevy TrailBlazer LT 4X4 Summit White - 4.2L I6 P10, lifted, wheels, etc.

  6. #6
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    Quote Originally Posted by joecar View Post
    Lower the 1->2 WOT MPH (and make sure to keep the 2->1 WOT MPH lower than it), and lower the 1->2 WOT RPM until you see the shift...
    Truck will go like 50mph in first, rpm point is set to 6000... Still wont shift

    Quote Originally Posted by ScarabEpic22 View Post
    Stupid little things first:
    Did you change the ratios?
    Did you adjust the shift points?
    Did you use the A4 trans spreadsheet to make sure the upshift/downshift tables don't cross? (Ive found this makes or breaks a trans tune.)

    If you can, post the tune so we can check it out. If not, feel free to email it to me: <my username> @gmail.com.
    Yes I did all those things as well...
    Attached Files Attached Files
    -John

    1991 RCSB 2WD Sierra LQ4 swap, 220/224 112 cam, Twin VSR 6766 turbos
    4L80e w/shift kit, PY 3600, and 3.73 gears.
    22 PSI and E85, 4300# with driver. 9.7@138, 1.47 sixty
    :drivin:

  7. #7
    Joe (Moderator) joecar's Avatar
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    Hi John,

    The WOT downshift MPH should be set lower than the corresponding WOT upshift MPH...

    yours are the opposite (higher), see this in your tune file (this keeps it downshifted, i.e. no WOT 1->2 shift):

    Click image for larger version. 

Name:	4L80E WOT shiftpoints backwards.png 
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    Also, set the Throttle kickdown tables to 100% in all cells.

  8. #8
    Joe (Moderator) joecar's Avatar
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    And, after making the WOT downshift MPH's lower than the corresponding WOT upshift MPH's, lower the WOT RPM's to get the shifts...

    then once you see it doing those shifts, slowly increase the WOT RPM's and/or the WOT MPH's until it shifts at the desired RPM and/or MPH.

  9. #9
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    Are those tables gonna make a difference at 40+ mph? I want it to shift at like 45-50mph at 6800 RPM.
    -John

    1991 RCSB 2WD Sierra LQ4 swap, 220/224 112 cam, Twin VSR 6766 turbos
    4L80e w/shift kit, PY 3600, and 3.73 gears.
    22 PSI and E85, 4300# with driver. 9.7@138, 1.47 sixty
    :drivin:

  10. #10
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    Over on performancetrucks.net guys were saying it was because I didn't have my ISS sensor hooked up...
    -John

    1991 RCSB 2WD Sierra LQ4 swap, 220/224 112 cam, Twin VSR 6766 turbos
    4L80e w/shift kit, PY 3600, and 3.73 gears.
    22 PSI and E85, 4300# with driver. 9.7@138, 1.47 sixty
    :drivin:

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