2025 4Runner Transmission Overheating on Climbs Off-Road

[Gunnison]

2025 OR Premium Hybrid - Anybody else having problems with their transmission overheating on offroad climbs? And if so, what have you done to fix it? Transmission temperature is normal and shifts normally on paved mountain highways but overheats on off-road climbs (medium-long) - 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. Dry conditions. I know some Tacomas were having this issue.

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[brumey]

Following this. No input from me yet.

 

[Burgi]

I experienced the same thing last time I was off road in 4x4. I was going down a pretty rutted out dirt road with a few small climbs at like 15 mph. After about a mile I saw the transmission temp climb. I stopped for a couple minutes and put it in 4lo and it went back to normal temp.

 

[CrispyTacoLover]

Some Tacoma owners are reporting this…

https://www.tacoma4g.com/forum/thre...ing-on-long-climbs-off-road.12606/post-157673

 

[Coldwiz]

Use 4 Low whenever you can if speeds are low enough and if you aren't using 4 Low, use the manual shifting mode on the transmission and use the lowest gear you can and let the engine Rev more. That should help keep transmission temperatures down. Same thing as when towing, manual mode and use a lower gear.

 

[timelapse]

I’ve read about these issues on the new Tacoma. Insane to think these new Toyota’s aren’t capable for simple things that they’re intended to do. Never had any issues in 230k on my 5th gen driving to high altitude trailheads. No issues yet on my 6th, but have only done a 2400’ gravel climb so far. On the Tacoma side, people can’t make it up basic gravel FS roads without overheating if it’s a sustained climb over 3,000’ or so. Unacceptable. And more often than not 4H and especially 4L is not needed for forest roads.

 

[DangItsDen]

Well that's not great to hear... Curious how widespread this is and how affordable/easy a transmission cooler is to install...

 

[Gunnison]

Use 4 Low whenever you can if speeds are low enough and if you aren't using 4 Low, use the manual shifting mode on the transmission and use the lowest gear you can and let the engine Rev more. That should help keep transmission temperatures down. Same thing as when towing, manual mode and use a lower gear.

The 6th gen doesn't have a manual shifting option unless I'm missing something haha - isn't the somewhat equivalent of this putting it in sport mode which still is automatic

 

[Gunnison]

Took it the dealer today for them to tell me what I expected - that they couldn't find anything wrong because obviously there are no hills nearby for them to test it on, so they said to submit a case to Toyota so Toyota can share additional software information with them that they apparently don't have access to. At least Toyota will then see "officially" that there is an issue and if others with 4Runners and Tacomas submit their cases hopefully that will lead them to do something about it.

 

[Coldwiz]

The 6th gen doesn't have a manual shifting option unless I'm missing something haha - isn't the somewhat equivalent of this putting it in sport mode which still is automatic

Most toyotas are like this now. My 18 tundra and 22 tacoma shifters are the same way. Once in D, push the shifter to the left and you enter S mode where you can manually make gear changes. It won't let you overrev the engine but it will let you hold lower gears when needed if it won't overrev the engine.

 

[Gunnison]

I didn't even realize this was a thing, thanks! Such odd ways of "shifting" nowadays

 

[HVLA]

Took it the dealer today for them to tell me what I expected - that they couldn't find anything wrong because obviously there are no hills nearby for them to test it on, so they said to submit a case to Toyota so Toyota can share additional software information with them that they apparently don't have access to. At least Toyota will then see "officially" that there is an issue and if others with 4Runners and Tacomas submit their cases hopefully that will lead them to do something about it.

Hopefully they checked the fluid level?

 

[Gunnison]

Hopefully they checked the fluid level?

Nope. That would have required them unsealing the transmission (so stupid) and checking which would have been outside warranty apparently (dumb) and I would have had to pay for as general maintenance. Three dealerships I've talked to now and none of them seem to know diddly about the guts and workings of the 6G

 

[HVLA]

Nope. That would have required them unsealing the transmission (so stupid) and checking which would have been outside warranty apparently (dumb) and I would have had to pay for as general maintenance. Three dealerships I've talked to now and none of them seem to know diddly about the guts and workings of the 6G

Just because there isnt a dipstick doesnt mean you have to unseal anything. How do you think the fluid gets put into the transmission?

 

[HVLA]

Here is the procedure for the land cruiser. Same trans.

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