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Thread: What can be done to toyota tundra transmission?

  1. #1
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    What can be done to toyota tundra transmission?

    Hello,

    Wondering if anyone has played with the tundras shifting?

    I really hate the delay in the "s"mode, would like it to shift when I tell it to instead of waiting a few seconds, pretty useless as is.

    Also OV tuning claims to have a tune that is exclusive to them and allows you to hold the transmission in gear. Is that possible with hp tuners?

    Anything else you've played around with?

  2. #2
    Holding gears is easy, just drop the shift points - look at the tow/haul shift scheduling tables in the attached tune as a crude example.

    Admittedly, in practice I use a low, non-zero number for everything other than the 1-2 shift, so I'm not sure what it decides when everything is zero'd out, I'll have to play with that.

    That being said, there's just not really much point to holding other gears (3-6) all the way to a standstill, and I find that I only really use the "gear hold" to do high load, low RPM logging and on the rarest of occasions on a back road.

    As far as delay with the shifter, nothing much we can do with that, better to just leave it in drive to get good WOT shifting (a manual 1-2 is especially hopeless) and just treat "S" as a range select. If it's any consolation, it's pretty common gripe across makes.
    Attached Files Attached Files

  3. #3
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    Thanks! I will play with that then, before buying this sequoia I drove some audi's and BMW's ect. They all seemed to have terrible "s" mode seems like it is mostly a marketing feature and completely useless I thought the 6spd yukon denali was better so was hoping this could be improved. It's never as good as a real stick and clutch though I guess.

  4. #4
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    I'm interested in getting a Tundra, but what might be a deal killer right now is that I can't shift it from 2nd to 1st over 2000 RPMs. Is there a way to change this so that it shifts from 2nd to 1st using manual mode at a higher RPM???

    Thanks.

  5. #5
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    Quote Originally Posted by SlowNStock View Post
    Holding gears is easy, just drop the shift points - look at the tow/haul shift scheduling tables in the attached tune as a crude example.

    Admittedly, in practice I use a low, non-zero number for everything other than the 1-2 shift, so I'm not sure what it decides when everything is zero'd out, I'll have to play with that.

    That being said, there's just not really much point to holding other gears (3-6) all the way to a standstill, and I find that I only really use the "gear hold" to do high load, low RPM logging and on the rarest of occasions on a back road.

    As far as delay with the shifter, nothing much we can do with that, better to just leave it in drive to get good WOT shifting (a manual 1-2 is especially hopeless) and just treat "S" as a range select. If it's any consolation, it's pretty common gripe across makes.
    Would you mind throwing your file in the Toyota Repository Thread??

  6. #6
    Quote Originally Posted by Kev petron View Post
    I'm interested in getting a Tundra, but what might be a deal killer right now is that I can't shift it from 2nd to 1st over 2000 RPMs. Is there a way to change this so that it shifts from 2nd to 1st using manual mode at a higher RPM???

    Thanks.
    Played around with this a bit, wasn't able to manually command a downshift

    May be a workaround by raising the 2-1 shift point (and possibly the 1-2) and seeing if it will make the downshift on it's own in S2, but that's more than I care to play with it - it's just not a very useful shift

  7. #7
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    Thanks for the replies I haven't had time to play with it yet but this gives me something to start with

  8. #8
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    my 5-6 shift is a bit aggressive. What would you try to make it a bit smoother? Valve body is stock.

  9. #9
    Quote Originally Posted by korbiams View Post
    my 5-6 shift is a bit aggressive. What would you try to make it a bit smoother? Valve body is stock.
    The easiest/most straightforward way is to bump up the torque reduction for that shift under "Trans -> Torque Management -> Torque Reduction -> 5-6". Look at your log for the RPM where your rough shift occurs, then bump up the torque reduction in those rows, emphasize on the higher torque cells - just spitballing, I would wager a 10% bump in the 2500 RPM row, from 148 lb-ft on up would give a good starting point.

    If you want a more deterministic answer, you can utilize the torque model to identify specific cells via the below procedure:

    1) Log the RPM and TPS % where the rough shifts occur.
    2) Look up the equivalent throttle angle for the logged TPS in "Engine -> Airflow -> Electronic Throttle -> Desired Throttle Angle -> 5th" - you may need to interpolate.
    3) Look up the estimated torque at your throttle angle and logged RPM under "Engine -> Torque Model -> Optimum Torque Trans".
    4) Increase the value in the 5-6 Torque Reduction cell corresponding to the logged RPM and estimated torque - you may (and often will) need to adjust several cells as the table is coarse and your RPM/torque pairing won't fit neatly into just one cell.

    You'll still need to use some judgement on exactly where and how much you want to adjust at each step, but this will narrow down your search a bit

  10. #10
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    Quote Originally Posted by SlowNStock View Post
    The easiest/most straightforward way is to bump up the torque reduction for that shift under "Trans -> Torque Management -> Torque Reduction -> 5-6". Look at your log for the RPM where your rough shift occurs, then bump up the torque reduction in those rows, emphasize on the higher torque cells - just spitballing, I would wager a 10% bump in the 2500 RPM row, from 148 lb-ft on up would give a good starting point.

    If you want a more deterministic answer, you can utilize the torque model to identify specific cells via the below procedure:

    1) Log the RPM and TPS % where the rough shifts occur.
    2) Look up the equivalent throttle angle for the logged TPS in "Engine -> Airflow -> Electronic Throttle -> Desired Throttle Angle -> 5th" - you may need to interpolate.
    3) Look up the estimated torque at your throttle angle and logged RPM under "Engine -> Torque Model -> Optimum Torque Trans".
    4) Increase the value in the 5-6 Torque Reduction cell corresponding to the logged RPM and estimated torque - you may (and often will) need to adjust several cells as the table is coarse and your RPM/torque pairing won't fit neatly into just one cell.

    You'll still need to use some judgement on exactly where and how much you want to adjust at each step, but this will narrow down your search a bit
    Thanks mate. You are the best!!!!
    Will try these changes later today.
    You would not believe how much tuners charge us over here.....really appreciate it.

  11. #11
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    Quote Originally Posted by SlowNStock View Post
    The easiest/most straightforward way is to bump up the torque reduction for that shift under "Trans -> Torque Management -> Torque Reduction -> 5-6". Look at your log for the RPM where your rough shift occurs, then bump up the torque reduction in those rows, emphasize on the higher torque cells - just spitballing, I would wager a 10% bump in the 2500 RPM row, from 148 lb-ft on up would give a good starting point.

    If you want a more deterministic answer, you can utilize the torque model to identify specific cells via the below procedure:

    1) Log the RPM and TPS % where the rough shifts occur.
    2) Look up the equivalent throttle angle for the logged TPS in "Engine -> Airflow -> Electronic Throttle -> Desired Throttle Angle -> 5th" - you may need to interpolate.
    3) Look up the estimated torque at your throttle angle and logged RPM under "Engine -> Torque Model -> Optimum Torque Trans".
    4) Increase the value in the 5-6 Torque Reduction cell corresponding to the logged RPM and estimated torque - you may (and often will) need to adjust several cells as the table is coarse and your RPM/torque pairing won't fit neatly into just one cell.

    You'll still need to use some judgement on exactly where and how much you want to adjust at each step, but this will narrow down your search a bit
    I could not find Torque Management under Trans

  12. #12
    Quote Originally Posted by korbiams View Post
    I could not find Torque Management under Trans
    You may need to submit a ticket and see why that table isn't available - https://support.hptuners.com/index.php?/Tickets/Submit

    There are other ways around it, but you really need to be able to access that table to do it correctly

  13. #13
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    Quote Originally Posted by SlowNStock View Post
    The easiest/most straightforward way is to bump up the torque reduction for that shift under "Trans -> Torque Management -> Torque Reduction -> 5-6". Look at your log for the RPM where your rough shift occurs, then bump up the torque reduction in those rows, emphasize on the higher torque cells - just spitballing, I would wager a 10% bump in the 2500 RPM row, from 148 lb-ft on up would give a good starting point.

    If you want a more deterministic answer, you can utilize the torque model to identify specific cells via the below procedure:

    1) Log the RPM and TPS % where the rough shifts occur.
    2) Look up the equivalent throttle angle for the logged TPS in "Engine -> Airflow -> Electronic Throttle -> Desired Throttle Angle -> 5th" - you may need to interpolate.
    3) Look up the estimated torque at your throttle angle and logged RPM under "Engine -> Torque Model -> Optimum Torque Trans".
    4) Increase the value in the 5-6 Torque Reduction cell corresponding to the logged RPM and estimated torque - you may (and often will) need to adjust several cells as the table is coarse and your RPM/torque pairing won't fit neatly into just one cell.

    You'll still need to use some judgement on exactly where and how much you want to adjust at each step, but this will narrow down your search a bit
    is there any good ways to firm up the shifts or speed up? im super new to tuning in general, and trying to learn as much as i can. for instance my tuned truck shifts pretty good, but if i hear the new rams or silverados that are tuned shifts it sounds like they shift in milliseconds lol. sorry if this sounds really noobish, im super new

  14. #14
    Quote Originally Posted by GearOne2019 View Post
    is there any good ways to firm up the shifts or speed up? im super new to tuning in general, and trying to learn as much as i can. for instance my tuned truck shifts pretty good, but if i hear the new rams or silverados that are tuned shifts it sounds like they shift in milliseconds lol. sorry if this sounds really noobish, im super new
    You can increase Base Line Pressure ("Transmission -> Shift Pressures -> General") for the gears you want to firm up/decrease shift time. Make conservative changes, say 5% or less at a time, focus on the higher throttle positions (say 30-40% TPS or above), blend it into the lower TPS cells, and leave the maximum values alone (which should match PCS Line Max, and should also be left alone).

    You can try to work with torque management ("Transmission -> Torque Management"), emphasizing higher torque and RPM areas. Try to reduce 5-10% at a time to get a little firmer shift, and make these changes separately from pressure changes. Again, don't go too far here, just enough to firm up the shifts to your liking; whiz bang shifts might feel quick, but often aren't (and are sometimes actually slower). Part of what makes the transmissions you reference shift so well is well-tuned torque management.

    There's lots of bad advice out there for transmissions - deleting torque management, scaling the entire pressure table an arbitrary amount, cranking up max pressures, etc. - the reality is the OEMs don't leave lots "on the table", and it's difficult to gauge the net mechanical effect of our tuning changes (a firmer shift may decrease clutch wear, but increase shock loads, more line pressure may increase temps from additional friction or it may decrease from reduced slip, etc.). The name of the game is conservative changes, making iterations, and not straying too far from the baseline - without good reason, I wouldn't go beyond 10-15% additional pressure or 20-25% less torque management.

  15. #15
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    Quote Originally Posted by SlowNStock View Post
    You can increase Base Line Pressure ("Transmission -> Shift Pressures -> General") for the gears you want to firm up/decrease shift time. Make conservative changes, say 5% or less at a time, focus on the higher throttle positions (say 30-40% TPS or above), blend it into the lower TPS cells, and leave the maximum values alone (which should match PCS Line Max, and should also be left alone).

    You can try to work with torque management ("Transmission -> Torque Management"), emphasizing higher torque and RPM areas. Try to reduce 5-10% at a time to get a little firmer shift, and make these changes separately from pressure changes. Again, don't go too far here, just enough to firm up the shifts to your liking; whiz bang shifts might feel quick, but often aren't (and are sometimes actually slower). Part of what makes the transmissions you reference shift so well is well-tuned torque management.

    There's lots of bad advice out there for transmissions - deleting torque management, scaling the entire pressure table an arbitrary amount, cranking up max pressures, etc. - the reality is the OEMs don't leave lots "on the table", and it's difficult to gauge the net mechanical effect of our tuning changes (a firmer shift may decrease clutch wear, but increase shock loads, more line pressure may increase temps from additional friction or it may decrease from reduced slip, etc.). The name of the game is conservative changes, making iterations, and not straying too far from the baseline - without good reason, I wouldn't go beyond 10-15% additional pressure or 20-25% less torque management.
    Why are these trucks set to shift so early at WOT? Just started messing with a 17 tundra and noticed this.