2022 Transmission High Temp Alarm

I did post this on a Tundra facebook group already but am curious if anyone here has had this issue.

I love this truck however I am having a high temperature issue with my transmission.

The truck has a Westcott kit and 35’s.

My camper is 740lbs and today, with it empty (no gear or water), and just me in the truck with my bike on the back I got the “transmission high temperature warning, see owners manual” for my second time.

Both times I’ve gotten this alarm on the dash I’ve been in 4Hi on an inclined FSR with an ambient temperature of approx 75F.

Today the route was so short (2 miles on a gravel road at 20mph, 8% grade) that I kind of discounted the alarm as a nuisance but it actually rang in a few times and I noticed it started to become a bit jerky, as if the torque converter was really getting a workout.

When I pulled over there was no smell of any kind luckily.

It’s booked in with Toyota next week but curious if anyone else has had a similar issue?

I'm wondering if perhaps the fluid level is low, although it could just be the big tires and pretty maxed out on weight. If that's the case it's a little disappointing as my '20 Taco had no issues doing the exact same thing and even more overloaded.

 

If weights an issue I’d be in alarm all the time.. pulled 9900lbs 580km 2 weeks ago on highway nonstop. And certainly more then enough hills to push its limits.

 

I've not had this issue yet but are you in drive or selectable. I had a 2014 5.7 and was backing my 16' enclosed up along driveway and I got a trans temp notification. I put it in 4lo and was good. If you're in drive, I'm thinking the truck is trying to be in too high of a gear and causing it to heat up.

 

Both times it was just in drive. Then downshifted to 1 after the first alarm but I’d guess it’s too late at that point.

The road was so mellow that I really didn’t think it needed 4low. I’ve rarely used 4Low in 30 yrs of driving fsrs. Only used it in the past if it was exceptionally loose or steep. I’d say I used it more on descents than climbs.

 

https://youtu.be/lOPSi2AYGMA

Watch this video from minute 1:34. Apparently, you're not supposed to take the truck over 50mph on 4Hi. I don't really tow so i don't know if theres advantages towing 4wd over 2wd, but any reason why you can't tow with 2WD?

 

I wasn't suggesting you use 4low. I did cause I was on a steep driveway with a loaded trailer. I was thinking in your case that maybe put it in select mode and maybe in 2nd or 3rd if you're only going 20mph.

 

Great video. He is not saying don't go above 50 MPH in 4HI. What he is saying, is that because the system is "on the fly" activation, dont activate it if the truck is travelling over 50 mph at the time. Once its activated you can go over 50 mph.

The general rule for towing in 4hi is, If your are in terrain and or weather that would warrant 4 wheel drive without the trailer, it also warrants it with the trailer. Just a general rule.

 

Drive faster. I think the torque converter locks at higher speed and higher gears. Driving long distances with the torque converter unlocked will heat it up immensely. Or use 4Lo.

 

Some 2.5 Gens overheated while going slow in 4wd. I think that and the added weight was was why your truck had the alarm.

The dealer will probably say everything is fine cause the alarm is off now. Some would suggest doing a drain and fill of your trans fluid since it got that hot. Since this isn’t the first time your got the alarm, get a scangauge or some other way to monitor your trans temp to see what cause it to rise.

 

Gotcha. Thanks for the clarification.

 

Did they bring back the trans cooler for you guys? Without it, going slow in 4x can cause excessive heat.

 

This is not as uncommon as you might think, and it’s normal given what you’re doing with your truck. 4Hi at lower speeds over uneven terrain is not friendly to transmission temps, especially when towing. As others have said, your torque converter stays unlocked and generates heat. Consistent load + unlocked = rapidly climbing temps.

I’d get something to monitor your temps with. I use the Veepeak Bluetooth OBD reader paired with the Fusion app on my phone. It’s on any time I’m off-road or towing.

 

Somebody on one of the FB groups yesterday mentioned getting this exact same message while pulling their 5,000 lb travel trailer in a mountain area on the interstate....

 

User error. Never make your truck do any real work (towing, especially at low speeds, or crawling while loaded down) in 4hi.

 

So driving on the interstate in 2WD is user error?

 

Ahh, I think I misunderstood...I took "in a mountain area" to mean in 4hi. My bad. In that case, might just be not enough truck.

I only tow in S4 unless I'm on a dead flat stretch of road. I constantly monitor transmission temps and lockup status on my Fusion app. S4 is what keeps me locked the best, particularly on long and/or steep grades.

I do think towing or crawling while loaded down in 4hi is user error. The transmission will run so much cooler in 4Lo.

 

Yeah, anytime the TC isn't locked up it's going to be making a lot of heat. 4LO is definitely a way to help prevent this.

 

*unlocked

 

Why can't Toyota just put a decent transmission cooler setup in their trucks. My Lexus GX is the same way, 250F transmission temps the first time I towed with it, even backing way out of the throttle once I was in the 230's. The thing that was most obnoxious is that, even when I would pull over to let it rest the trans temps wouldnt come down. I think the factory cooling system that uses the radiator end tank would stop cooling once the engine coolant temps dropped because the coolant was no longer flowing through the radiator, and so the trans fluid was barely being cooled.

And maybe thats the issue here. Maybe the engine in the Tundra wasnt being stressed and so flow through the thermostat had dropped and wasnt passing through the radiator and cooling the transmissions cooler.

I added a hayden cooler and now it won't break 205F no matter what I do. My GX unlocks its converter ALL the time which is part of the issue, but it can easily be overcome with an adequate cooler. And now, because I have the air cooler, it will always be cooled because the mechanical fan will always be pulling at least some air through the stack.

My F150's transmission never gets over ~210F and the thermostat only opens at ~198. I've towed my trailer all over Utah, offroad and on.

 

That's a good idea on the scan gauge. With all the doohickeys on this truck you'd think it would have that displayed already, like my long dead 93 GMC 2500 did. Interesting as I used to rally that old pig doing the same thing without issue. It certainly didn't have the power this truck does but perhaps the transmission was heavier duty even though it was old?

I also am reading between the lines and agree I need to get better suspension so I can go faster over rough terrain.

 

I'm wondering if an aftermarket cooler could be added?

My dealer has only sold 20 of these trucks and they have reported that another customer was getting the same alarm towing his boat at 70mph in 2hi on the highway. Perhaps the cooler just isn't up to the task? Very different loads and speeds however. Hauling vs towing...

I just did a large trip through BC on mountain highways and had no issue on pavement. Truck handled it with ease it seemed, except in the slow 4wd situation Io originally discussed.

 

Can you explain how this works to me? (Because I'm a dumbass!)

 

The transfer case is after the transmission, so the gear reduction is happening after the transmission which means less stress is applied to the transmission to complete the same task.

 

I've had this message towing our pontoon boat before. I stopped at a gas station to fill up and then had a 10 minute drive to our Airbnb up some windy hilside neihborhood roads. I was in 2H and tow/haul mode and got the message. Hasn't come back, even after pulling our boat up Parleys Canyon in Utah. Maybe just the slow climbs are too much for the trans cooling?

 

It’ll happen in 2Hi or 4Hi because the torque converter is unlocked at low speeds. The difference with 4Lo is that much less engine torque is required to keep going due to the transfer cases’ gearing. So with the low gearing the torque converter is heated up much less. Also there are two temperature sensors on the Tundra just like the 2nd gen. One in the pan and one in the torque converter. Based on my testing the torque converter sensor heats up super quickly compared to the oil pan.

 

You could use tow haul + as it will hold a gear higher and you'd experience much less TC slippage or just manually put it in a lower gear and leave it there. Not sure what RPM the TC locks up in this tranny or if it is capable of locking in 1st/2nd, etc gears

 

If multiple people are getting this message on pavement in 2hi, I wonder if 3rd gens are going to need an external cooler kit like the 2nd gens.

Thoughts on the 3rd gen’s 10 speed:
Your 10 speed has 3 overdrive gears: 8, 9, and 10. 7th gear has the 1:1 ratio. If it operates in the same way as the prior gen’s 6 speed, your transmission will hold lockup in 7th and in all of the overdrive gears. On the 2nd gen’s 6 speed, 4th gear is 1:1, and it can hold lockup in 4 and in its two overdrive gears, 5 and 6. This is why I tow in S4 (gear ratio of 1:1) unless cruising on relatively flat terrain. I’m preventing gear hunting (and the associated unlocking of the TC). It helps to use an OBD app like Fusion to monitor lockup status in addition to pan and TC temps.

Hope that helps. My pan temps have not exceeded ~200ºF ever since installing an external cooler following my method outlined above.

 

3rd Gen torque converter is basically locking up in 2nd gear with light throttle. But with heavy throttle, 2nd and 3rd have the torque converter unlocked. I definitely recommend some kind of monitoring app since the standard gauges don’t give much information about temps.

 

I just received a Scangauge 3.

The stock configuration shows the trans temp and lock up status however I thought there were two transmission temperatures? Pan and Converter. I can only see one.

Anyone have the manual codes for the two transmission temps on the ‘22 tundras? I can’t seem to find them on the scangauge website.

 

I've discussed this with Scangauge and run their data logger on my 2022.

After they looked through the log data they don't think there's a second sensor available to monitor.

@ScanGauge Any further info?