2024 Tacoma Transmission Overheating on Long Climbs Off-Road

[bsquaredMTB]

I just experienced this yesterday while out on a very easy dirt road. I was in 4 hi and probably didn't need to be but I did overheat. Once I got back on road and was able to get back to 2wd and higher speeds the truck cooled down. My AC was also not cooling at all at lower speed. I opened my window and heard a whistling. Turns out coolant was spraying out of the cap. I had to let the truck cool. I'm taking it in to the dealer tomorrow. I'll let you guys know what they say. Also of note is that I had JUST had the 15k maintenance the day before. I'm a little suspicious they messed something up.

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[ATacoInAZ]

2024 OR Premium Hybrid - Anybody else having problems with their transmission overheating specifically on long offroad climbs? And if so, what have you done to fix it? Transmission temperature is normal and shifts normally on mountain highways but the truck overheats on long off-road climbs - anything over about 600m (~2000ft) vertical. I've had warning lights come on twice and now monitor the transmission temperature on climbs and stop for a couple minutes then continue once the transmission cools. I'm not towing or carrying anything more than a couple mountain bikes. These are roads I've done in other trucks and done in tandom with other vehicles and the other trucks including a couple 3G Tacomas and Bronco are not overheating their transmissions. I've tried 4 LOW which shouldnt be necessary on these grades but it doesn't really help. I've asked my dealer about it and was told to install a transmission cooler if I'm going to be doing a lot of offroading. I'll for sure do this but just expected an OR vehicle to not overheat on offroad climbs... Any other solutions people have found?

I heard this was an issue for the 2024 and they fixed it for the 2025

 

[james cole]

I heard this was an issue for the 2024 and they fixed it for the 2025

fixed how?

 

[hadelson]

Yeah, I'd be interested to see what they say about that. Would they actually have the balls to tell you that you can't drive your off road truck in 4wd and that you were doing something wrong?

I have no doubt the dealer would tell you this. Toyota Quality and CS is pretty crappy these day compared to 7-8 years ago. Have an issue now the TH front end alignment. Dealer claims in specs but cannot answer why front tires ruined in 3500 miles due to excessive outside edge wear.

 

[cranny]

I heard this was an issue for the 2024 and they fixed it for the 2025

Dunno. Hope that's true! Switching to manual shift, I could see that the transmission was staying in 3rd gear even on steep sections of road in 4 HIGH. Switching to manual and dropping to 1st or 2nd gear depending on grade and RPM fixes the problem. I could do the same climbs at the same speed and transmission temp stayed dead centre instead of climbing to near max or setting off an alarm. Seems like the auto transmission needs a tweak

 

[TacoFreak]

Dunno. Hope that's true! Switching to manual shift, I could see that the transmission was staying in 3rd gear even on steep sections of road in 4 HIGH. Switching to manual and dropping to 1st or 2nd gear depending on grade and RPM fixes the problem. I could do the same climbs at the same speed and transmission temp stayed dead centre instead of climbing to near max or setting off an alarm. Seems like the auto transmission needs a tweak

Good information! It sounds like the transmission is overheating by not down shifting and is just letting the torque converter do the work. That would explain the overheating and why manual shifting fixes the problem. It would be great if a TCU software update fixes the problem, and hopefully Toyota is working on that now.

 

[maxx075]

Good information! It sounds like the transmission is overheating by not down shifting and is just letting the torque converter do the work. That would explain the overheating and why manual shifting fixes the problem. It would be great if a TCU software update fixes the problem, and hopefully Toyota is working on that now.

This is incorrect on the fact that the manual mode always displays S3 when you shift it over and is not an indication of what the current gear is. The manual mode on the auto trans acts as a limiter. Whatever is displayed means that the trans will not shift above that gear, not that that is what gear it is currently in.

 

[TacoFreak]

This is incorrect on the fact that the manual mode always displays S3 when you shift it over and is not an indication of what the current gear is.

True, so we are still stuck with off road trucks that don't work well off road and have not idea if or when that might be fixed.

 

[BAQ717]

@JustDSM wondering what you think of these 4HI transmission overheat issues - is this something you noticed during the tuning R&D?

 

[james cole]

@JustDSM wondering what you think of these 4HI transmission overheat issues - is this something you noticed during the tuning R&D?

we are about to see how much they really know of if they are selling porky pies. @JustDSM

 

[bsquaredMTB]

I just experienced this yesterday while out on a very easy dirt road. I was in 4 hi and probably didn't need to be but I did overheat. Once I got back on road and was able to get back to 2wd and higher speeds the truck cooled down. My AC was also not cooling at all at lower speed. I opened my window and heard a whistling. Turns out coolant was spraying out of the cap. I had to let the truck cool. I'm taking it in to the dealer tomorrow. I'll let you guys know what they say. Also of note is that I had JUST had the 15k maintenance the day before. I'm a little suspicious they messed something up.

Update: I took the truck in today and they said that the connectors to the fans were loose causing them not to kick on to keep the engine cool enough. They plugged the in correctly and flushed the coolant in the truck. I have ABSOLUTELY NO clue if that's a reasonable thing or not. What do you guys think? Is this something they should check out during regular maintenance or is it possible that those plugs just happened to be loose?

 

[Gunnison]

2024 OR Premium Hybrid - Anybody else having problems with their transmission overheating specifically on long offroad climbs? And if so, what have you done to fix it? Transmission temperature is normal and shifts normally on mountain highways but the truck overheats on long off-road climbs - anything over about 600m (~2000ft) vertical. I've had warning lights come on twice and now monitor the transmission temperature on climbs and stop for a couple minutes then continue once the transmission cools. I'm not towing or carrying anything more than a couple mountain bikes. These are roads I've done in other trucks and done in tandom with other vehicles and the other trucks including a couple 3G Tacomas and Bronco are not overheating their transmissions. I've tried 4 LOW which shouldnt be necessary on these grades but it doesn't really help. I've asked my dealer about it and was told to install a transmission cooler if I'm going to be doing a lot of offroading. I'll for sure do this but just expected an OR vehicle to not overheat on offroad climbs... Any other solutions people have found?

Just got a new 2025 OR Hybrid 4Runner (~2,000 miles), drove it from Colorado back to California mostly off-road and am having the exact same issues, with no extra load. Happens in 2 and 4H. Tow mode helps. On roading is fine. I am bringing it to the dealer tomorrow to see what they say.

 

[TacoFreak]

I am bringing it to the dealer tomorrow to see what they say.

Good! This is happening way too often and Toyota needs to come up with a fix.

 

[maxx075]

I've seen two now that had the BSM issue fixed and dealership forgot to plug the fan connectors back in...

 

[Gfenza89]

Good! This is happening way too often and Toyota needs to come up with a fix.

Another transmission fiasco on these 4th gen’s

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