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Thread: ZF8HP70 fails 1>2 shift under WOT

  1. #1
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    ZF8HP70 fails 1>2 shift under WOT

    In attached log i see the 1>2 is commanded at 5740rpm, then some TQ mgmt is applied,
    but it never shifts and hits rpm limiter around 6700rpm. Normal street driving is ok. Anyone see this?

    Recent Mods:
    MMX Max Effort NA cam kit
    longtube headers & hi-flow cats
    Circle D 3600rpm stall converter
    Hellcat throttle body
    180 degree thermostat

    2019 Dodge Challenger Scat Pack 6.4l
    Attached Files Attached Files

  2. #2
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    I don't think I'm hitting a tq/safety-type limit (initially) so all I know to try is add more TQ Mgmt (more than stock) and increase Shift Timing. I've already added a good amount of Shift Pressure. Open to other suggestions/feedback.

    Car only dyno'd at 475whp/485tq so I'm surprised its having so much trouble w/ shifting but the high stall converter could explain it.
    Last edited by shak3r; 10-13-2021 at 02:15 PM.

  3. #3
    Looks like you need a lot more Torque pulled out so the trans can actually shift it with the crazy high Pressures you're commanding.

    You're in MAX mode during the shift that's barely pulling any Torque,( -54Nm according to that tune).
    Sport and Normal mode pull close to -300Nm.

    An easy test is to lower the pressures back to stock in 1st Gear and switch to Normal mode and see what happens.
    Last edited by duster360; 10-17-2021 at 11:50 PM.

  4. #4
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    Thanks for the reply.

    Yes, during that pass it was in Max mode which is somewhat of a fluke as its usually in Sport such as this pass (log attached). Notice in pass3 a good bit of TQ Mgmt is applied, and trans commands 1>2 shift at 5737rpm but it still pushes through the shift. The rpm drops very slowly (not sharp) when TQ Mgmt is applied for unknown reason.

    pass3_Graph.JPG

    https://www.dropbox.com/sh/gdv6qshf8...-garfGPaa?dl=0

  5. #5
    Quote Originally Posted by shak3r View Post
    Thanks for the reply.

    Yes, during that pass it was in Max mode which is somewhat of a fluke as its usually in Sport such as this pass (log attached). Notice in pass3 a good bit of TQ Mgmt is applied, and trans commands 1>2 shift at 5737rpm but it still pushes through the shift. The rpm drops very slowly (not sharp) when TQ Mgmt is applied for unknown reason.

    pass3_Graph.JPG

    https://www.dropbox.com/sh/gdv6qshf8...-garfGPaa?dl=0
    Lower 1st gear pressure back to stock so the C clutch has an easier time releasing.

    You can turn the Fuel Cut back on too
    Last edited by duster360; 10-19-2021 at 09:10 AM.

  6. #6
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    Thanks for the feedback! I'll try those suggestions this Saturday at a TNT event.

    To clarify, stock trans settings would not complete 1>2 shift either under WOT at prep'd track. But in hindsight that may have been more related to the shift schedule (too late shift) than anything else. i.e. The OSS rpm is way different bet/ the stock and 3600 stall converter.
    Last edited by shak3r; 10-19-2021 at 11:53 AM.

  7. #7
    Quote Originally Posted by shak3r View Post
    Thanks for the feedback! I'll try those suggestions this Saturday at a TNT event.

    To clarify, stock trans settings would not complete 1>2 shift either under WOT at prep'd track. But in hindsight that may have been more related to the shift schedule (too late shift) than anything else. i.e. The OSS rpm is way different bet/ the stock and 3600 stall converter.
    If you were slipping bad in 1st even with the Stock Trans tune, you may just have a transmission issue ei: smoked E clutch.

    Once the converter is over its stall speed, the OSS isn't going to vary much from stock, even if its not a stock modified converter.

  8. #8
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    Yesterday I ran 6 passes total:

    1st pass: Did not complete 1>2 shift
    2nd pass: Completed 1>2 shift using only 60% accelerator pedal.
    3rd pass: Did not complete 1>2 shift
    4th pass: Completed 1>2 shift using <54% accelerator pedal. (Bracket elimnation round)
    5th pass: Completed 1>2 shift using <48% accelerator pedal. (Bracket elimnation round)
    6th pass: Did not complete 1>2 shift using ~100% accelerator pedal (Bracket elimnation round - eliminated)

    A common theme when shift does not complete is the Clutch Shift Type is somehow getting set to MAX. In later tune revs I tried to disable MAX w/o much luck.
    All passes were ran in Track drive mode so I was adjusting shift schedule pattern 9 throughout day.

    Link to logs/tunes and vids below. Thanks for any feedback!

    https://www.dropbox.com/sh/d2swqd44d...mWIz3G6na?dl=0

  9. #9
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    NVM, I'm going to cut my losses and move on from the 3600 Circle D converter. I've got at 1320 torque converter (2350 stall) on order. The Circle-D converter will be up for sale -- might work better on the (HP70) RAM trucks?

  10. #10
    Sorry to be late to this but did you ever figure out the problem. Im haveing the exact same issue as you, but ive git a 5.7 with a factory convertor
    2019 challenger rt
    k&N cold air intake
    92mm hellcat throttlebody
    ported 392 intake manifold
    ported eagle heads
    Cammotion custom 222/234 cam
    stainless works long tube headers and catless mid pipes
    3' catback with h-pipe & pypes violator mufflers
    e-85 tuned

  11. #11
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    what's the price you'd be willing to let that 3600 circle D go for? I've got a 2016 Ram with a stage 3 cam that would be a perfect match for that stall size i think...
    2016 Ram CCSB Forged NA 396ci Stroker
    +1.5cc Flat top Mahle Power-Pak Forged Pistons w/13.2/1 CR on E85
    Forged Manley 4.05" Stroke Crank
    Race Ported Eagles/Titanium 2.10"/Titanium 1.62" Valves
    Self-Designed Custom Grind 236/249 .629/.629 111LSA 110ICL+1Adv
    Ported Holley Hi-Ram Intake/NXpress Hi-Ram NO2 Plate kit w/250 Shot(4 sec)
    Tx Spd 2" Prim LT Headers/Active Viper Hood/2-Step Launch
    ATI SD w/15% UD/Hellcat Pump/Demon 700cc Inj
    Edge Pro Conv w/3800 stall/Det Tru-Trac/410 Gears

  12. #12
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    Just confirming replacing the 3600 Circle D w/ a 1320-spec'd model resolved my shift issue. The Circle D wanted to flash to the moon (6600+ rpm) which was not realistic w/ stock pistons. A 3k spec might have worked.

    I already sold the Circle D to guy w/ a RAM

  13. #13
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    I actually also have one of the 1320's installed in my 2016 Ram but havent quite made it out for a drive just yet. trying to iron out this trans engine torque request or whatever is putting me into limp mode and Ive also come to the realization that my timing almost had to jump a tooth so Ive got the front of the motor torn apart as we speak and am resetting all the timing marks now and hopefully have that wrapped up sometime tonight. Im hoping the timjing is the cause for all these issues but Im not holding my breath or anything. But I myself am quite curious of how this 1320 converter with its lower stall set at 2350 is going to fair with my Ram setup. Its the one move Ive made that Ive been second guessing and going back n forth over. Worried it may not be enough on mine as far as the stall size goes anyway. How is your setup fairing for you using the 1320? Is it what you expected? And how exactly did you go about tuning for this particular converter? Any feedback and/or advice is much appreciated!
    2016 Ram CCSB Forged NA 396ci Stroker
    +1.5cc Flat top Mahle Power-Pak Forged Pistons w/13.2/1 CR on E85
    Forged Manley 4.05" Stroke Crank
    Race Ported Eagles/Titanium 2.10"/Titanium 1.62" Valves
    Self-Designed Custom Grind 236/249 .629/.629 111LSA 110ICL+1Adv
    Ported Holley Hi-Ram Intake/NXpress Hi-Ram NO2 Plate kit w/250 Shot(4 sec)
    Tx Spd 2" Prim LT Headers/Active Viper Hood/2-Step Launch
    ATI SD w/15% UD/Hellcat Pump/Demon 700cc Inj
    Edge Pro Conv w/3800 stall/Det Tru-Trac/410 Gears

  14. #14
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    I essentially kept the stock trans (including TQ) settings of my Scat. If you talk to 1320 guys you will hear about intermittent bad shifts. I choose not to blindly import their trans tune settings to avoid that headache. I improved my 60' slightly (less than .10) w/ the 1320 converter. My best so far is 1.670 (2078 DA).

  15. #15
    Quote Originally Posted by shak3r View Post
    Just confirming replacing the 3600 Circle D w/ a 1320-spec'd model resolved my shift issue. The Circle D wanted to flash to the moon (6600+ rpm) which was not realistic w/ stock pistons. A 3k spec might have worked.

    I already sold the Circle D to guy w/ a RAM
    you did nothing else but switch the stall convertor? ive been debating getting one for the same reason as you because ive had no luck fixing the 1-2 shift not happening via the trans tune. i just really dont want to spend $1000 on the convertor and hundreds more in labor for nothing. i dont really race my car, its a daily, but i do enjoy having fun
    2019 challenger rt
    k&N cold air intake
    92mm hellcat throttlebody
    ported 392 intake manifold
    ported eagle heads
    Cammotion custom 222/234 cam
    stainless works long tube headers and catless mid pipes
    3' catback with h-pipe & pypes violator mufflers
    e-85 tuned

  16. #16
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    If you have a stock TC it should be shifting w/o issues so I'd be hesitant to replace the TC too. Are you sure you're not hitting a max TQ limit vs rpm limiter? Did you post tune/logs/vids like i did above?

    FYI, read this post about some (3) of the TQ limit tables. This is not an inclusive list but may be helpful...
    https://forum.hptuners.com/showthrea...l=1#post665706

    I'm sure my stock TC would have worked fine but I opted to upgrade to a 3600 during cam swap and it never worked correctly. I reverted to a 1320 TC and its been working fine w/ stock trans tune.
    Last edited by shak3r; 06-04-2022 at 09:06 AM.

  17. #17
    Quote Originally Posted by shak3r View Post
    If you have a stock TC it should be shifting w/o issues so I'd be hesitant to replace the TC too. Are you sure you're not hitting a max TQ limit vs rpm limiter? Did you post tune/logs/vids like i did above?

    FYI, read this post about some (3) of the TQ limit tables. This is not an inclusive list but may be helpful...
    https://forum.hptuners.com/showthrea...l=1#post665706

    I'm sure my stock TC would have worked fine but I opted to upgrade to a 3600 during cam swap and it never worked correctly. I reverted to a 1320 TC and its been working fine w/ stock trans tune.
    trans tune 6-22.1.hpt
    engine tune 5-22.2.hpt

    these are my trans and engine tune right now, I haven't been able to confirm if it works or not. i see your torque convertor doesn't engage 1st-5th, is there a reason for that?
    also i do not believe i am hitting a torque limit
    2019 challenger rt
    k&N cold air intake
    92mm hellcat throttlebody
    ported 392 intake manifold
    ported eagle heads
    Cammotion custom 222/234 cam
    stainless works long tube headers and catless mid pipes
    3' catback with h-pipe & pypes violator mufflers
    e-85 tuned

  18. #18
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    Quote Originally Posted by shak3r View Post
    In attached log i see the 1>2 is commanded at 5740rpm, then some TQ mgmt is applied,
    but it never shifts and hits rpm limiter around 6700rpm. Normal street driving is ok. Anyone see this?

    Recent Mods:
    MMX Max Effort NA cam kit
    longtube headers & hi-flow cats
    Circle D 3600rpm stall converter
    Hellcat throttle body
    180 degree thermostat

    2019 Dodge Challenger Scat Pack 6.4l
    Same Issue!
    1-2 holds @ 50% or lower throttle, above that will trigger rpm limiter and limp mode.
    WOT shifts from 2nd or higher are fine. Prefer to resolve 1-2 shift issue before dyno.

    comp 270 cam kit
    ported heads
    whipple 2.9L @10.3lbs boost
    long tube headers
    Circle D 2800rpm stall converter
    90MM upgrade throttle body
    180 degree thermostat
    6.4L w/forged internals

  19. #19
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    Quote Originally Posted by Enthusiastic View Post
    Same Issue!
    1-2 holds @ 50% or lower throttle, above that will trigger rpm limiter and limp mode.
    WOT shifts from 2nd or higher are fine. Prefer to resolve 1-2 shift issue before dyno.

    comp 270 cam kit
    ported heads
    whipple 2.9L @10.3lbs boost
    long tube headers
    Circle D 2800rpm stall converter
    90MM upgrade throttle body
    180 degree thermostat
    6.4L w/forged internals
    Hello!

    Could you share your tune and log?

    DodgeBoy.
    YouTube: https://www.youtube.com/@dodgeboy2785

  20. #20
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    Quote Originally Posted by Enthusiastic View Post
    Same Issue!
    1-2 holds @ 50% or lower throttle, above that will trigger rpm limiter and limp mode.
    WOT shifts from 2nd or higher are fine. Prefer to resolve 1-2 shift issue before dyno.

    comp 270 cam kit
    ported heads
    whipple 2.9L @10.3lbs boost
    long tube headers
    Circle D 2800rpm stall converter
    90MM upgrade throttle body
    180 degree thermostat
    6.4L w/forged internals
    how did that dyno session go?