Torque converter lockup in 10 speed.

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.

 

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.



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.

 

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

 

@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?

 

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

 

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.

 

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.

 

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.

 

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.

 

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.

 

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

 

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.

 

Has anyone found a definitive answer to when lockup occurs? It does feel like like lockup is happening in low gears in this truck. 3+?

 

3rd gen Tundra can lock up from 2nd gear, I believe trans temp + load and drive mode determines when it locksup.

For me in eco mode and 9th gear anything above 12.5 psi in the manifold and tcu commands slip and it holds the gear till 20.5 psi.

 

Is this car scanner? I couldn't get TC lockup to show anything.

 

I run a scanguage 3, and I have convertor lockup and gear usage info. This is such a useful tool to observe and monitor so much information. It sure beats the heck out of the Edge CTS I run in my powerstroke Excursion.

Mike

 

Yeah its car scanner, if you wanna run it on your truck there are a lot of threads on it. If TC lockup pid isn’t showing 1 or 0 you might need to select 2016+ profile for Toyotas.

 

Thanks. I'll do some poking around.

This is my profile right now:

 

That's the profile I'm using and I am able to see TC lockup state. Will check tomorrow which PID i used.

 

@Retroboy1989
This is torque converter sensor.


This ones the current gear.


I think I know why your pid might not be showing up.You might be selecting the wrong PID, I believe there’s a duplicate that doesn’t work on the third gen. Hope the screenshots help.

 

This is a huge help. I got it working. Thanks for your help.

With 10 gears, it shifts so many times, it doesn't seem like the app keeps up with tc lock pid before it's moved to the next gear and unlocked again

 

I'd be interested to see if yours locks and unlocks as much as mine. Just a slight uphill grade and mine unlocks (or at least car scanner says it does). Also did a bit of playing around on a recent road trip and found on level ground the transmission won't go into 10th until 78mph but it will stay in 10th until speed drops below 73mph. Gave me something to do on interstate 90 in South Dakota.....

 

I haven't experimented with it much yet. I'm sure I will want to share what I observe. I am feeling more confident that the "double shift" I was noticing was actually the TC locking after each gear change.

I was scared my trans was slipping between gears.

I've added an aftermarket trans cooler so I would rather not have a warranty issue on the trans incase Toyota blames the cooler.

 

Toyota likes to play with us like that I had the same damn thought when I felt the jerkiness during shifts.

Mine unlocks on hills too but I feel like it helps the motor build boost quicker. Either way I wonder what the trans fluid will look like at 60k with all the transient spikes from shifting and unlocking.

 

Driving home from work today, countless shifts, locks and unlocks.

It's generally accepted around here that the 10spd generates more heat than the 5.7 6spd did. There is a thread out there somewhere with low mile trans fluid pics from the 10spd. It's dark.

I generally do annual drain/fill on my transmissions. The new tundra will get that treatment religiously.

I've also noticed my truck likes to stay in third gear unless I stop almost completely. It doesn't like rolling stops as it feels over geared getting rolling again.

 

Does anyone know if the torque app will show gear and trans lock?

 

I was in the camp of, "my truck always shifts perfectly" with no perceptible TC lock/unlock bothers that others have reported. But, after I recently towed ~5,000 lb trailer 200 miles, my truck doesn't seem to be shifting the same. I can feel what, to me, feels like a delayed shift engagement and downshift that feels like the TC struggling to unlock. I'm only at 10k miles right now, way too soon to need a trans flush, but I'll probably start there. Was SO smooth, now it's kind of clunky...

 

That's my experience as well in SD (only on I29 instead) +/- 80 MPH cruise engaged before it will actually shift into 10th gear. Runs around 1700 RPM at that point.

(80 MPH is posted speed limit on South Dakotas 2 interstate highways)

 

Need help. I have a 2025 and cannot get trans temp to show. What BT adaptor are you using. Any help would be appreciated.

 

Many of us are running a scangauge device which is a monitor which connects to the OBD port. I run the SG3 which has 3 screens of 9 PIDs to monitor. Hope this helps.

Mike