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Torque converter lockup in 10 speed.

Discussion in '3rd Gen Tundras (2022+)' started by TTund16, Jan 6, 2022.

  1. Jan 6, 2022 at 4:58 PM
    #1
    TTund16

    TTund16 [OP] New Member

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    What gears does the torque converter (TC) lock in gen3 10-spd transmission?

    In the old 6 gear models, TC locks in 4th, 5th and 6th. iirc, lockup can also occur in 3rd gear if the temp gets above certain limit (275F?). Not %100 sure about the 3rd gear lockup temperature.

    New models (Gen3) have 10 gears ... Curious what gears it can lock? 6th and up? iirc, 6th in gen3 is 1:1

    I assume constantly changing gear or hunting for gears between 6th and 10th can cause a lot of unlocking especially when towing.What is the recommended gear for towing in gen3?

    Gen 2.5 recommended 4th for towing to reduce excessive TC unlocking which produces heat and extra wear & tear.
     
  2. Jan 6, 2022 at 5:12 PM
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    xc_tc

    xc_tc New Member

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    This is from the Toyota global website. The 8-speed is probably the one from Land Cruiser/LX or maybe Lexus IS/GS/LS. Anyway looks like lockup will be increased. My best guess it will lock up in all gears except maybe 1st and 2nd.

    0FBF04C7-2ACE-4BF4-8834-65448A24BAD1.jpg

    The 22 Tundra has two tow modes so select the one you want based on trailer weight to get the optimal gear. I would only use the manual select going downhill otherwise it will needlessly hold a lower gear and keep revs too high.
     
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  3. Jan 6, 2022 at 6:09 PM
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    TakiEvo

    TakiEvo New Member

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    Straight from Toyota TiS. Looks like 7th gear is 1:1 ratio.

    2E6F1C1C-B2DC-4101-9E2C-A1B0FD6AB456.jpg
     
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  4. Jan 8, 2022 at 2:14 PM
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    TTund16

    TTund16 [OP] New Member

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    @xc_tc @TakiEvo ,

    You guys think there could be a potential lugging in high(er) gears and how is that managed?

    also does gen3 have a recommended or specified gear for towing (e.g. gen2.5 4th) or is it managed automatically?
     
  5. Jan 8, 2022 at 3:45 PM
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    stevj

    stevj New Member

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    Typically, the transmission will downshift to obviate lugging.
    As far as a recommended gear for towing: the highest gear that will allow torque converter lockup.
    Unfortunately, however, no manufacturer I'm aware of provides an indicator that will tell you when the torque converter is locked.
    Folks that tow could use such a thing for the peace-of-mind it can provide those concerned about transmission temps.

    Steve
     
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  6. Jan 8, 2022 at 4:45 PM
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    TTund16

    TTund16 [OP] New Member

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    you are right about the lockup.
    Some of the apps will give you that info.
    I use scangauge and can tell by the temperature diff if locked or not.

    Typically extended lockup when towing and in 4th. That's what gen2.5 owner's manual also recommend.

    I guess for gen 3 maybe max 7th or even 6th! Or let the car decide since according to @xc_tc gen3 has 2 tow modes.
     
    Last edited: Jan 8, 2022
  7. Jan 8, 2022 at 5:40 PM
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    xc_tc

    xc_tc New Member

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    Yeah, I don’t think the transmission would let the engine lug and it seems that Tow/Haul keeps the revs up. I would recommend towing with Tow/Haul or Tow+ and seeing if that’s comfortable.
     
  8. Jan 8, 2022 at 6:14 PM
    #8
    Rockgate

    Rockgate New Member

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    I'm thinking the 2 different tow/haul modes are just different throttle curves for the pedal. They may alter shifting but I doubt it'll limit itself to a certain gear.
     
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  9. Jul 19, 2022 at 2:22 PM
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    Toyoworker

    Toyoworker New Member

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    Hi there. As an owner of 2022 SR5 CrewMax Sport 4X4 I can try and answer some of these questions. First of all I believe by the feel of this transmission that once it is up to a certain operating temperature it will lock the torque converter in 2nd through to 10th gear. As a Toyota employee I have owned a 2018, 2019, 2020, and 2021 model Tundras with the 5.7 engine now this 2022. When this transmission up shifts it immediately locks up the torque converter after each and every gear change. Same on the downshift. It never seems to run with it unlocked and hence building heat. The tow haul programming is fantastic especially compared to the last generation. Our family has a 26ft Jayco camping trailer that we regularly haul around. It is upwards of 6,000lbs loaded up and shaped like a brick so it is a good load for these trucks at highway speeds. The tow haul + setting seems to work best for this trailer. At 60 miles per hour highway speeds it will just sit in 7th gear at about 2,000rpm and rarely shift unless you encounter a decent hill. The last generation trucks in comparison would be constantly changing gears unless you locked it into S4 mode and let it rev. I am very impressed with the calmness and power of this new drivetrain. Despite it having 10 speeds it does not hunt for gears. Ironically the old 6 speed was far worse for that in towing applications. With this new one just leave it in drive, select the tow mode that works best for the size and weight of trailer that you’re towing. I have used the regular tow haul mode with our trailer but find it will upshift to 8th gear on the highway and a slight grade will cause it to downshift to 7th so a bit of gear hunting occurs. This 2 stage tow haul mode is brilliant. The gear range selection is more dictated by speed on this truck than load when using the tow modes. You can try driving with just the truck using the tow modes and it will limit gears by speed. I mean this by it won’t shift out of 7th in tow haul + until you reach more than 70miles per hour for example whether it is just the truck or our 6,000lb trailer behind. It selects the appropriate gear for the speed and engine rpm. Seems like the powertrain engineers have really sharpened their programming skills on this new model. Any other questions regarding anything with this new generation of truck I will try to answer.
     
    Last edited: Jul 19, 2022
    mayan, stack101 and TTund16[OP] like this.
  10. Jul 19, 2022 at 3:05 PM
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    TTund16

    TTund16 [OP] New Member

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    Good info. Sounds like the new design is smarter!

    I wanted a v8 Tundra with a 5-spd manual trans like my Tacoma but the 6-spd auto ain't that bad with the sequential mode and I can select a gear. It won't be confusing and only 3 options while cruising either 4,5 or 6th gear. Mostly only 2 gears (4th, 5th) while towing for me.

    If I had a 10-spd with the new design, I would select the tow mode and probably just leave it in D and let the ECU decide.
     
    Last edited: Jul 19, 2022
  11. Jul 19, 2022 at 4:14 PM
    #11
    Toyoworker

    Toyoworker New Member

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    The only real advantage I have found is if I am towing over constantly changing terrain, I have put it in tow + and S7 so that when you approach a significant hill you can drop it down to S6 before the hill so that it doesn’t downshift under heavy load as you start to climb. Easier on the transmission this way. Also handy when going down a long grade if you want to manually downshift to provide some extra engine braking
     
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  12. Jan 16, 2023 at 7:40 AM
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    mayan

    mayan Texas BBQ and Beer

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    Is there a way to see which gear the truck is in? Sometimes when I'm trying to conserve momentum the transmission jerks a lot I live in the DFW area so I do this a lot to the truck any tips on this? I best way I can describe the feeling is to imagine if you are coasting at 20 mph in the lowest gear allowed by the truck and its engine braking but as soon as you start to feather the throttle you feel a clunk that sinusoidally reduces in force you can feel 2-3 peaks but after the shifts are unnoticeable. Might be just me but I have felt this in 4x4 models and the dealer disagrees but only a friend has agreed with me on this clunk thing.
     

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