Transmission Overheating - anyone else?

[RideWithYanu]

Just another report on the issue, nothing new:

Yesterday I experienced the transmission temp raise up to the point that it initiated a warning. I had been ripping through some remote dirt roads pretty hard, pretending I was back in my rally days. Around 5k ft, and all uphill (quite steep in most areas). 4-Hi, everything unlocked. Again, really going full beans on it. Once I reached the trail I was looking for I began the real climb, still in 4-Hi. Once I got the dash alert (I had noticed the transmission temp rising) I went ahead and shut the engine down and took the chance to walk the trail a ways to make sure it was going to be wide enough. I returned to the truck about ten mins later and the temp was back down to about 3/4 of the gauge (I can’t recall the actual temp). After that point I went down to 4-Lo and carried on with a close eye on the temps; they continued to drop down to normal temps, and didn’t rise again for the rest of the day.

 

[jarussell4]

Coming from the Jeep World...That is not normal in other vehicles. As the first person who reported on this thread said, even CRV's and Subarus can go up on drive and not have any issues. On the Jeeps, it has to get very steep for it to use 4lo, on the 4xe, you almost don't need 4lo ever.
I went all in on Toyota for its reliability and I do not feel so comfortable now, really starting to regret the change.On top of all I am only getting 16-17mpg on freeway and driving 70 and below.
Took it to the dealership today and the technician was surprised on both (the transmission going up on the temp and the mpg). They will do a full check and call Toyota. I am really hoping Toyota backs their vehicle as much as they talk about it. Will post an Update soon...

 

[RideWithYanu]

Coming from the Jeep World...That is not normal in other vehicles. As the first person who reported on this thread said, even CRV's and Subarus can go up on drive and not have any issues. On the Jeeps, it has to get very steep for it to use 4lo, on the 4xe, you almost don't need 4lo ever.
I went all in on Toyota for its reliability and I do not feel so comfortable now, really starting to regret the change.On top of all I am only getting 16-17mpg on freeway and driving 70 and below.
Took it to the dealership today and the technician was surprised on both (the transmission going up on the temp and the mpg). They will do a full check and call Toyota. I am really hoping Toyota backs their vehicle as much as they talk about it. Will post an Update soon...

They have a very, very long history of standing behind their vehicles. I suspect they will continue to do so.

 

[Bad1975]

I know that some of the folks that were towing with the new Tundra's were pinning the Thermostat open and it was helping, others were adding and external cooler. You can search more on www.tundras.com

Is it safe to pin open Transmission thermostat?

I might take you up on that thermostat. I honestly haven’t crawled underneath yet to look for the warming puck. I was mulling things over last night...

www.tundras.com

I wouldn’t recommend that, that is part of the fluid level adjust procedure that help the transmission reach operating temperature faster. Just like a radiator thermostat removed will cause an engine to overheat under load the same will occur with a pinned trans stat.

Either install a larger trans cooler or get a dedicated fan with thermostat for the OEM cooler.

I haven’t looked at 250s cooler but I’d bet it’s likely coolant and air cooled like most OEM coolers these days?

The coolant if using that type isn’t helping do much cooling especially if the rad fan is off and is more ideal for aiding to increase the fluid to operating temp quicker in cold climate/winter conditions and keeping the trans fluid in the AF coolant temp range when possible.

 

[jarussell4]

UPDATE:
Took it to the dealership yesterday 6/10 at 2:00 pm and Have not heard back as of today 6/11 at 4:30. I can see from the app notifications that they are opening and closing the front driver's door few times a day and the hood has remained open as well as the fron windows...so they are doing something. I will post more once they call me. I will not call yet as I want to give them time to run any type of tests they have to.

Will keep you posted

 

[jarussell4]

Picked up vehicle. They did extensive tests on it andas others have posted here, they did not find anything.
But the tech told me that the graphic gauge on the dash is really more of a warning than a true representation of the temp. Basically telling yo to either change the mode, put it in manual or try different driving style. He stated that they looked at all the data from the ECU and it never went over 190. That warning I got, was just that, a warning and that it directed me to page 223 (I think) on thge manual which says to either let the tranny rest or change modes. Tundras with the 8 speed have had the same issue (which apparently is not an issue).
So I will be using the car scan as someone suggested in this forum (Cool Carplay Dashboard with OBD Scanner ) and project it on my screen with the temp, maybe I can also find the Torque Converter temp on it too as the Tundras do. Here is also the link to the thread on the Tundra forum (LINK). Hope this helps.
I am just getting used to Toyota I guess. The Jeep used to give me the actual temp for the tranny, oh well.
I mean, it behaves normal and I can't feel any slippage (eventhough the dealer said that from the data they did see some from my offroad adventure, but they state is normal). I am taking it to a trail near by this weekend to see how it behaves and connect the carscanner to monitor temps.
They also said the mpg was fine. I've been getting no more than 18mpg on freeway. Maybe changing the engine oil might help. Is sitting at 1050 miles now and I had 400miles of offroad trails. So maybe changing the oil might help.

 

[RideWithYanu]

Picked up vehicle. They did extensive tests on it andas others have posted here, they did not find anything.
But the tech told me that the graphic gauge on the dash is really more of a warning than a true representation of the temp. Basically telling yo to either change the mode, put it in manual or try different driving style. He stated that they looked at all the data from the ECU and it never went over 190. That warning I got, was just that, a warning and that it directed me to page 223 (I think) on thge manual which says to either let the tranny rest or change modes. Tundras with the 8 speed have had the same issue (which apparently is not an issue).
So I will be using the car scan as someone suggested in this forum (Cool Carplay Dashboard with OBD Scanner ) and project it on my screen with the temp, maybe I can also find the Torque Converter temp on it too as the Tundras do. Here is also the link to the thread on the Tundra forum (LINK). Hope this helps.
I am just getting used to Toyota I guess. The Jeep used to give me the actual temp for the tranny, oh well.
I mean, it behaves normal and I can't feel any slippage (eventhough the dealer said that from the data they did see some from my offroad adventure, but they state is normal). I am taking it to a trail near by this weekend to see how it behaves and connect the carscanner to monitor temps.
They also said the mpg was fine. I've been getting no more than 18mpg on freeway. Maybe changing the engine oil might help. Is sitting at 1050 miles now and I had 400miles of offroad trails. So maybe changing the oil might help.

Very helpful update. Thank you!

 

[quattr0]

They also said the mpg was fine. I've been getting no more than 18mpg on freeway. Maybe changing the engine oil might help. Is sitting at 1050 miles now and I had 400miles of offroad trails. So maybe changing the oil might help.

Sorry I joined late to this thread...Not sure if you tow anything or what else you've done to your LC. I have a 51 lbs Thule tub on the roof with my camping gears, a 38lbs Kammok awning, a 50lbs fridge/freezer, 2 power stations, a 38lbs Goal Zero 100w solar panel, non-stock Toyos AT3 tires and i'm consistently pulling 20..21mpg on freeway. I'm doing mostly 2-3mph more than posted speed limit. (77-78mph or whatever posted speed limit mostly).

You might give some more time on your LC. I have around 15k miles now.

 

[jarussell4]

Sorry I joined late to this thread...Not sure if you tow anything or what else you've done to your LC. I have a 51 lbs Thule tub on the roof with my camping gears, a 38lbs Kammok awning, a 50lbs fridge/freezer, 2 power stations, a 38lbs Goal Zero 100w solar panel, non-stock Toyos AT3 tires and i'm consistently pulling 20..21mpg on freeway. I'm doing mostly 2-3mph more than posted speed limit. (77-78mph or whatever posted speed limit mostly).

You might give some more time on your LC. I have around 15k miles now.

Not even close...but it only has 1100 miles. Time will tell. More concrned about the tranny than the mpg right now.

 

[NoMe cruiser]

My tranny hasn’t got severely warm yet. I was pushing through some deep, packed snow last winter with the undercarriage dragging the whole time, occasionally locking the center differential and using MTS. Temperature outdoor ~20F. Transmission got near the red zone but never in it nor did it throw a code. I was running 255/70/18 blizzaks. I have not seen any mention of tire size in any of these posts. If I had tried to push 285/70 through that snow the tranny may have overheated due to the increased rolling resistance, maybe not. I just see a lot of people putting on 285’s and I’m wondering if there may be a link to big, wide aggressive tires going balls to the wall and transmission’s overheating??? You guys with overheating issues, what size tires are you running?

 

[jarussell4]

Well, mine is pretty much stock with a victory roof rack. Original tires (which, by the way, they are not as bad as they look). Wished they came with 17's for better deflation behavior on the tires and driving on dirt uphills and switchbacks at about 80 F. Again if I switched to manual it will cool way down according to the screen or 4lo as well.
Just remember that the dealership told me that gauge is really not a gauge, is just a read out from a sensor that serves as a warning. So the CarScanner will serve as that gauge for real temps.
Mine never gave me the Engine light, it was just a warning to stop and read the manual.
Once I get my new skids, I will take it to the backroads and it will probably be closer to 90 degrees, so it will be a good test.
I will keep y'all posted.

 

[RideWithYanu]

My tranny hasn’t got severely warm yet. I was pushing through some deep, packed snow last winter with the undercarriage dragging the whole time, occasionally locking the center differential and using MTS. Temperature outdoor ~20F. Transmission got near the red zone but never in it nor did it throw a code. I was running 255/70/18 blizzaks. I have not seen any mention of tire size in any of these posts. If I had tried to push 285/70 through that snow the tranny may have overheated due to the increased rolling resistance, maybe not. I just see a lot of people putting on 285’s and I’m wondering if there may be a link to big, wide aggressive tires going balls to the wall and transmission’s overheating??? You guys with overheating issues, what size tires are you running?

Great point! I’m running 285/70R17 tires in E load rating. They are definitely heavy…

 

[ct1958]

MPG will improve after you have about 4k on the clock. I'm consistently getting 25 - 26 MPG on the highway driving 70-75m MPH. Bone stock 58. My best was 27.6

 

[ferrari1898]

I have a 25 1958 no cooling issues so far. I can attach the diagram the shows the cooler and location. If you’re towing or off-roading a lot I would maybe just upgrade the cooler. Mishimoto makes a good kit for example.

We have towed our camper some 4k miles with the Land Cruiser and have not seen the transmission temp gauge jump much. While not towing it is pegged in the middle around the icon (ussually on toward the left). While towing it creeps to the right side of the icon. I have toyed with an external cooler, but at least in my experience there is not much need.

That said we are towing 3500lb (plus gear). We head out today to the Smoky's with some decent mountain roads to deal with since I40 is closed (again). We will see how the Toyota does today with temps in the low 90s. Next week we head to PA and have to drive up I77 and Fancy Gap

 

[Justaron123]

We have towed our camper some 4k miles with the Land Cruiser and have not seen the transmission temp gauge jump much. While not towing it is pegged in the middle around the icon (ussually on toward the left). While towing it creeps to the right side of the icon. I have toyed with an external cooler, but at least in my experience there is not much need.

That said we are towing 3500lb (plus gear). We head out today to the Smoky's with some decent mountain roads to deal with since I40 is closed (again). We will see how the Toyota does today with temps in the low 90s. Next week we head to PA and have to drive up I77 and Fancy Gap

I haven’t had any issues towing with mine either. I’ve towed a dump trailer. Also a few smaller cars. It has done fine.

 

[ferrari1898]

Coming back from the Smokys yesterday I did see the transmission temp tick up to about 75% on the scale before retreating down to just past 50% near the right of the icon. Since I40 is shut down, we had a windy mountain road and it was very slow going for a few miles. Once we started to move, not issues. Additionally, it was low-mid 90F outside. Friday we head to West Virginia and have to climb Fancy Gap in the summer which will be interesting. We did it in the spring and the transmission temps were fine. I am curious to see how the weather will impact it this time. I really do not expect any issues, rather just the gauge to rise a little more dramatically.

 

[jarussell4]

Alright I have an update.
I took it to a local trail here near San Diego, CA (Black Mountain trail near Ramona, CA). I've done the trail several times with my other vehicles in 4x2 without a priblem and always at about 195F on the dot for the tranny of those other vehicles.
Unfortunately for this new LC 250 was not the case, I hooked up the OBDII scanner and projected on my carplay using carscanner and the Only sensor that measures any tranny temp (Transmission Pan Temperature Sensor#1) and it was HOT about after 1 mile into the trail. The gauge stayed at 3/4 of the way all the way up the easy dirt trail (granted it was 90F outside). Did not give me any warnings but is stayed between 225 and 235F the whole entire way according to carscanner. On the way home it never went below 215F, eventhough the gauge showed half way. Is this normal for Toyotas??????, I am not used to this high of temps on my other vehicles ever and my last one also had an 8 speed transmission. This time it never gave me any messages, but the tranny temp gauge on the LC stayed right at 3/4 the whole way up.
I wonder if there is anyone else out there who is paying attention to your tranny temp gauge while on the trails?

 

[jarussell4]

Here is what I found so far for our 8 speed trannys:
For the 2024-2025 Toyota Land Cruiser 250 (LC250) with the 8-speed automatic transmission, typical transmission fluid temperatures under various conditions are as follows:


Normal highway driving:

• ~150-180°F (65-82°C)

Moderate off-road trails / mild inclines (without 4LO):

• ~180-210°F (82-99°C)

Steep uphill trails, slow crawling, sand, or heavy throttle without using 4LO:

• Temperatures can rise to 220-240°F (104-116°C), especially if you remain in higher gears without the torque multiplication and cooling benefits of low range.

Warning range:

• Above 250°F (121°C) risks fluid degradation and potential overheating warnings or limp mode engagement.
• Toyota generally considers 260°F (127°C) critical for their recent 8-speed units.
  

 

[TakaraLC]

Scale on the temp gauge is not linear. This is also true for engine oil temp and coolant temp.

 

[jarussell4]

Good to know. Thanks. Still mind blowing on the temperatures, seems pretty high compared to other vehicles/trannies