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Thread: looking for a 8hp70 guru

  1. #1
    Tuner in Training
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    Apr 2022
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    23

    looking for a 8hp70 guru

    I HATE the way my Jeep SRT holds 4th gear on decel... it will literally hold 4th until 5mph and then will not down shift again when pressing the gas pedal only to sound like a 1st time manual driver riding the clutch.

    edit: when it sport or track it isnt as bad

    Now my Durango RT on the other hand does not do this. looking at the trans map there are significant changes and though they are the same trans they have different differential gear ration and not sure if i can simply copy and paste from one to the other.

    I fine with all the other gears just 4th drives me nuts. Is there anyone here that can help me with this change? it doesnt have to be from durango file, im just posting it for a comparision to the jeep. if someone can just help me get the trans to continue down shifting to say at least 3rd if not 2nd at lower speeds like that turning a corner that would be awesome.

    thank you

    jeep stock.hpt durango stock.hpt
    Last edited by Monstar; 12-02-2022 at 10:02 AM.

  2. #2
    Tuner
    Join Date
    Aug 2021
    Location
    Indianapolis Area
    Posts
    172
    Hello Monstar,

    Basically all shift points (shift schedule) while driving in Auto-Drive are less aggressive (fuel economy, maybe). Also, Torque Converter opens quite early (according to Dodge, to increase comfort).

    The way to fix it is:
    - Shift Schedule
    - Torque Converter
    - Shift Pressure
    - Torque Management (to mitigate shift elements stress)

    In case you are interested, I do offer personalized remote tune support. To give a little background about me: I have 12y of experience tuning transmission for Gasoline and Diesel engines. For the good of for the bad, all 12y are with ZF transmission (8HP). I already worked with: drag race, dune race, daily drive upgrades (shift comfort, shift schedule, fuel economy), drifting, ...

    Thanks.
    Dodge Boy

    Email: [email protected]

  3. #3
    Tuner EVguy1's Avatar
    Join Date
    Feb 2021
    Location
    Errington BC Canada
    Posts
    57
    After trying for the last year to tune my own and even tried some of the big name tuners, I finally have the perfect tune thanks to Dodge Boy. I also wanted increased engine braking during downshifting all the way to 1st gear and zero MPH.

  4. #4
    Quote Originally Posted by EVguy1 View Post
    After trying for the last year to tune my own and even tried some of the big name tuners, I finally have the perfect tune thanks to Dodge Boy. I also wanted increased engine braking during downshifting all the way to 1st gear and zero MPH.
    That is good to hear. I am having trans tune issues and may go to him in the spring when I get my car out of storage.

  5. #5
    Potential Tuner
    Join Date
    Nov 2021
    Posts
    5
    Quote Originally Posted by Monstar View Post
    I HATE the way my Jeep SRT holds 4th gear on decel... it will literally hold 4th until 5mph and then will not down shift again when pressing the gas pedal only to sound like a 1st time manual driver riding the clutch.

    edit: when it sport or track it isnt as bad

    Now my Durango RT on the other hand does not do this. looking at the trans map there are significant changes and though they are the same trans they have different differential gear ration and not sure if i can simply copy and paste from one to the other.

    I fine with all the other gears just 4th drives me nuts. Is there anyone here that can help me with this change? it doesnt have to be from durango file, im just posting it for a comparision to the jeep. if someone can just help me get the trans to continue down shifting to say at least 3rd if not 2nd at lower speeds like that turning a corner that would be awesome.

    thank you

    jeep stock.hpt durango stock.hpt
    You should be able to take the scheduling tables from the durango and copy to the jeep
    All the shift mapping is done based on output shaft speed, so the final drive ratio doesnt really make a difference

    Im used to the ram transmission tuning so 95% of normal driving without cruise or tow mode is map 0, 5 or 10
    Looking at your maps it seems to use all the tables, but map 5 has really low speed downshift points. Id start with that one

  6. #6
    Potential Tuner
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    Aug 2022
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    5
    PM sent to dodgeboy