2025 4Runner Transmission Overheating on Climbs Off-Road

[NotApplicable]

I look for this issue every time I’m off-road - constant scan of T’s & P’s just like any aircraft I’ve flown. I just haven’t had any issue at all. I do use a standard setup off-road (except Green easy stuff), 4Lo, S1-S3, SDM, MTS - Rear Locker or Crawl/Decent as required but that’s infrequent. I understand the frustration folks are having with this - it’s kinda’ like the brake squeal, just shouldn’t have to worry about it after the investment we made in the vehicle. I’ve used this setup over and over in high altitude, low altitude, cool temps, over 100 F ambient temps for hours, prolonged climbs/descents - no transmission overheat issues.

Makes sense, sounds like you aren’t using 4Hi which, based on reports, is required to cause the issue

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[a_double]

Having to use 4Lo on a paved moderate incline where there’s no chance for tire slippage is contrary to the owners manual.

 

[3rdRunner]

Having to use 4Lo on a paved moderate incline where there’s no chance for tire slippage is contrary to the owners manual.

Never use 4Lo on pavement, only off-road. If I was concerned about Transmission Temp I would use manual (S) or Tow/Haul - keep the engine revs higher. Understand and agree that this is certainly something we shouldn’t have to be worried about.

 

[ropdykex11]

Updating my thoughts on this:

Did a full weekend of REAL offroading, under multiple conditions. Fully loaded cargo, rooftop tent, racks, bumper, winch, everything.

Fast washboard roads, slow rutted crawling, rock crawling, steep articulated climbing.

4hi most of the time, 4lo when crawling.

I saw transmission temp spike SLIGHTLY from halfway to 3/4 max? (from a 5 to a 7, gage has no numbers), but otherwise no issues.

60deg ambient temp, not high elevation. I think if it was WAY warmer and higher elevation, it might have become an issue.

My current thoughts: not a major problem for my use case. I'd be interested in a transmission cooler upgrade if one becomes available, but otherwise NBD.

 

[Iconic Fabrication Offroad]

Updating my thoughts on this:

Its available! Let me know if you have any questions. Iconic Fabrication is a new paying vendor on this forum. 3/4 of the way up the gauge could be concerning. I don't have data on my personal 4runner of going that high but the gauge is not "accurate" so to speak. Dead center on the gauge tested anywhere between 140 to 200 degrees F on my 2026.

https://iconicfabricationoffroad.com/products/2025-4runner-transmission-cooler-kit

 

[RunnerRocks]

Between 140 to 200 degrees F and the gauge stayed dead center without moving ?

 

[Iconic Fabrication Offroad]

Between 140 to 200 degrees F and the gauge stayed dead center without moving ?

Yes! I tested this with my Veepeak OBD Scanner and several apps including Torque Pro and Car Scanner ELM apps.

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