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Thread: TCC Modes?

  1. #1
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    Default TCC Modes?

    Been logging my 80E. What is "AppEn" mode? i.e. what physical changes occur in the trans from "Off" to "AppEn" to "App" ?

    Edit: I found the reference material posted by joecar: http://forum.efilive.com/showthread....rence-Material
    The chart below describes the apply sequence. I presume that AppEn is stage 1. Now my questions are;

    1. Is there any situation where the PCM would only command stage 1 without proceeding to lockup?

    2. Can this generate excess heat? It appears that there is neither apply nor release pressure on the TCC during this stage. (release pressure is removed)

    * note this trans has been assembled to run full time high line pressure
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    Last edited by DrX; June 10th, 2013 at 06:58 AM.
    2017 Camaro SS, 2014 Ram 2500 4x4 Cummins 6.7L, 2004 Chevy Avalanche Z71 4̶X̶4̶(now 2WD), 5870lb race weight, 10.93@ 124, Twin TVS1900s, Twin Throttle, 429 LSX, 4L80E, custom 14 bolt rear, V2, R̶o̶a̶d̶R̶u̶n̶n̶e̶r̶(dead), COS3......
    Gettin' the Groceries

  2. #2
    Joe (Moderator) joecar's Avatar
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    AppEn is one of those in-between/transition states, usually the PCM would not stop there, it would either keep going or abort (if the load increases or misfires were detected).

    There is not enough pressure yet to engage the TCC, so the TCC should not be dragging...

    ( the TCC apply circuit has its own pressure regulator so would/should not be affected by increasing line pressure (this is done to prevent converted ballooning), unless modified by builder )


    if you suspect it is dragging then monitor TFT, TIS, TOS, TCCSLIP...

    also monitor ATF color/condition.


    You might want to set the Min TCC PWM table higher (and also set Max TCC PWM higher if not already).
    Last edited by joecar; June 10th, 2013 at 09:10 AM.

  3. #3
    Joe (Moderator) joecar's Avatar
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    Do you have any log files...?

  4. #4
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    I was looking at the AppEn feed (filtered 2-3 drive) to the TCC solenoid. At anything below around 45-50 MPH it just sat at AppEn and the temp kept climbing. After 20 min I was on a road where I could get the speed up a little higher and it was locked for about 10 min straight but did not cool down at all - it still climbed a couple more degrees. I think it was in the 230s when I pulled into the driveway. Will post the most recent log when I get home.

    The trans builder recommended maxing out the PWM. i.e no PWM
    2017 Camaro SS, 2014 Ram 2500 4x4 Cummins 6.7L, 2004 Chevy Avalanche Z71 4̶X̶4̶(now 2WD), 5870lb race weight, 10.93@ 124, Twin TVS1900s, Twin Throttle, 429 LSX, 4L80E, custom 14 bolt rear, V2, R̶o̶a̶d̶R̶u̶n̶n̶e̶r̶(dead), COS3......
    Gettin' the Groceries

  5. #5
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    Here is the log file.
    Attached Files Attached Files
    2017 Camaro SS, 2014 Ram 2500 4x4 Cummins 6.7L, 2004 Chevy Avalanche Z71 4̶X̶4̶(now 2WD), 5870lb race weight, 10.93@ 124, Twin TVS1900s, Twin Throttle, 429 LSX, 4L80E, custom 14 bolt rear, V2, R̶o̶a̶d̶R̶u̶n̶n̶e̶r̶(dead), COS3......
    Gettin' the Groceries

  6. #6
    Joe (Moderator) joecar's Avatar
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    230°F is bad... I would do whatever it takes to get TFT between 160°F-180°F.

    What are you using as a cooler...?

    ON/OFF is fine (you really won't mind the slight bump you feel).

  7. #7
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    I installed a new Tru Cool 40K cooler along with this trans. There is something in the tune or the trans that is causing the heat. I swapped out the converter and it made no difference.

    The TCC engagement was the same before I disabled the PWM - just a quick bump. It did not want to hold over 30% throttle though.
    2017 Camaro SS, 2014 Ram 2500 4x4 Cummins 6.7L, 2004 Chevy Avalanche Z71 4̶X̶4̶(now 2WD), 5870lb race weight, 10.93@ 124, Twin TVS1900s, Twin Throttle, 429 LSX, 4L80E, custom 14 bolt rear, V2, R̶o̶a̶d̶R̶u̶n̶n̶e̶r̶(dead), COS3......
    Gettin' the Groceries

  8. #8
    Joe (Moderator) joecar's Avatar
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    From your log it looks like you get lock when throttle is steady at 20%(+/-few%)... when unsteady below this it sees to cycle between AppEn and Off.


    Also, in your log, the TSTATE09-10 bit flags don't quite correlate to TCCDC% and TCCMODE...

    did you swap in 4L80E segment (seems like it)...? if so it may not be quite all the way compatible with your PCM (what it seems to me).

  9. #9
    Joe (Moderator) joecar's Avatar
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    That cooler is fairly large (about 1/2 the size of an engine coolant radiator), should get good quick cooling from that, even with the TCC unlocked, unless the TCC is dragging.

  10. #10
    Joe (Moderator) joecar's Avatar
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    Something is keeping the PCM from locking the TCC all the way (keeping it at AppEn).

    Something is causing the fluid to overheat.

    AppEn is a 4L60E term... but it seems you're using a 4L80E segment... (see what I mentioned about compatible above).


    sanity check:
    - is your cooler mounted in airflow...?
    - is it mounted with inlet/outlet at top or side (to avoid trapping air)...?
    - did you verify fluid flowing thru the cooler (about 2 quarts in 20-30 seconds)...?
    - are you seeing misfires...?
    - is the TCC brake switch steady in the OFF position...?
    - do you detect any problem with the converter does it seem too loose or too tight...?

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