2024 Tacoma Transmission Overheating on Long Climbs Off-Road

[Roly52]

Who makes the best trans cooler for towing? My trans overheats on a 60 degree day towing a 4000 lb trailer at 55.

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[Someguysomewhere26]

Only one I know of is Mishimoto. I haven’t seen any reviews yet.

 

[izzy]

Who makes the best trans cooler for towing? My trans overheats on a 60 degree day towing a 4000 lb trailer at 55.

Using S mode like the manual recommends? Pretty sure it says to keep it in 6th or below.

 

[Lando]

Using S mode like the manual recommends? Pretty sure it says to keep it in 6th or below.

Waiting to see the answer, as I will be towing a car on a trailer one day. About 4600 lbs.

Should be fine, or do I go back to a GM 1/2 ton?

 

[Someguysomewhere26]

If you’re going to be towing weight often unfortunately there’s definitely better options then the Tacoma.

That being said these transmissions are something.

 

[Independence Overland]

So here is my .02, as a long time Toyota owner.

My 07 Fj has always done this. It doesnt have a trans temp gauge. That thing has been loaded down for 16 years now, and I have driven all over the place. In early ownership, I owned it and never paid any attention or even thought about it. Once I installed the Ultragauge 6-7 years of ownership I was shocked by how hot my transmission was getting. 230+. What I learned was that even in 4L it would get hot if it was in D. If for instance I am in 4L, D, and I know for a fact its in 2nd gear and it starts getting hot, I can shift to 2nd gear in "manual mode" and it cools down immediately. I am assuming there is just more slippage and pressure buildup with the transmission anticipating a shift if you are in D, but in manual mode you lose that addtional heat.

When my Trailhunter still had the factory bed, but 35" tires and a bed rack/tent and towing a ~3k trailer, I saw temps climb while going up Aspen mountain which is a pretty steep climb, and takes roughly 20-30 minutes to summit. The truck was still pretty new to me, and I was learning the ins and outs. I saw it starting to heat up once on that trip, but only during that initial climb which was at night, but in October. I for sure was in 4L, but I believe I was just in D. I let it cool down for like 2 minutes tops and it was ready to go.

Flash forward and my truck is fully built and is certainly one of the heaviest out there. I did Redcone pass which is also a really steep climb for a good hour or two, and while I saw my temps start to rise, I am pretty aware of it and usually shift into manual mode and it cools itself off pretty quick. I did see it getting extra hot on a long section but I had to stop and wait for a friend anyway, so it naturally cooled down pretty quick.

I should add to this, Vail pass, steep highway stuff, no issues at all.

If you are going under 20mph off road, shift to 4 low. If its extra steep and starts to warm up, manually shift down. And don't wait until you get a warning to do so. I am willing to bet this will solve most of the issues people are having. Perhaps some summer desert driving will change my mind on this, but I have done some of that already and didnt have issues.
Its designed this way. And if you must haul ass up steep stuff in 2 or 4h, still try manually shifting, and get the RPMs to around 3k or better and you will be surprised how much better it does.

Excuse my dramatic thumbnails. Its the nature of the YT beast

Trailer steep climb video:


Redcone:

 

[Anamouse]

My 2025 4 door long bed Off Road Tacoma runs great except... the transmission overheats on slow steep uphill grades. I have to keep the dash view that displays the transmission temp on so I can see how hot it is and shut it down before it hits the red. It happens on steep paved roads with lots of tight turns, where I'm averaging about 15 -20 mph, so power is never an issue. If there was a 2wd low, I'd probably use it but I can't so I have to use 2wd high.

The dealer contacted the factory and they say they know this is a problem but don't have a fix. I am very concerned I'm doing permeant damage by creating varnish, and cooking my trans seals. I am pretty sure my trans wont' fail under warranty but I won't be surprised if it leaks in a few years and needs to be rebuilt in 10 years. I keep my trucks over 20 years and have never previously had a problem with a transmission in over 200K mile.

I believe a serous trans cooler is needed, with an electric fan on a temp switch. The trans should run at about 175°F to 225°F and I think it gets close to 300°F before the over temp switch cuts in and it cuts the engine power. When the engine is warmed up the radiator runs around 190°F to 220°F, keeping the trans fluid that runs through it close to that temp. Since this only happens at low speed when air flow is minimal, I think a fan is necessary. The engine temp is neve a problem so I don't think we need to improve the radiator, I just don't think the heat exchanger in the radiator is large enough to do the job.

The most heat would be removed if the trans cooler was before the radiator, to maximize the heat transfer from the trans fluid to the air, but the greatest reduction in trans fluid temp would be if we put the trans cooler after the radiator. The only concern there is that doing so might keep the trans cooler below the recommended operating temp in cold weather at higher speeds and less challenging terrane.

What you you think?

 

[MT-Taco]

So here is my .02, as a long time Toyota owner.

My 07 Fj has always done this. It doesnt have a trans temp gauge. That thing has been loaded down for 16 years now, and I have driven all over the place. In early ownership, I owned it and never paid any attention or even thought about it. Once I installed the Ultragauge 6-7 years of ownership I was shocked by how hot my transmission was getting. 230+. What I learned was that even in 4L it would get hot if it was in D. If for instance I am in 4L, D, and I know for a fact its in 2nd gear and it starts getting hot, I can shift to 2nd gear in "manual mode" and it cools down immediately. I am assuming there is just more slippage and pressure buildup with the transmission anticipating a shift if you are in D, but in manual mode you lose that addtional heat.

When my Trailhunter still had the factory bed, but 35" tires and a bed rack/tent and towing a ~3k trailer, I saw temps climb while going up Aspen mountain which is a pretty steep climb, and takes roughly 20-30 minutes to summit. The truck was still pretty new to me, and I was learning the ins and outs. I saw it starting to heat up once on that trip, but only during that initial climb which was at night, but in October. I for sure was in 4L, but I believe I was just in D. I let it cool down for like 2 minutes tops and it was ready to go.

Flash forward and my truck is fully built and is certainly one of the heaviest out there. I did Redcone pass which is also a really steep climb for a good hour or two, and while I saw my temps start to rise, I am pretty aware of it and usually shift into manual mode and it cools itself off pretty quick. I did see it getting extra hot on a long section but I had to stop and wait for a friend anyway, so it naturally cooled down pretty quick.

I should add to this, Vail pass, steep highway stuff, no issues at all.

If you are going under 20mph off road, shift to 4 low. If its extra steep and starts to warm up, manually shift down. And don't wait until you get a warning to do so. I am willing to bet this will solve most of the issues people are having. Perhaps some summer desert driving will change my mind on this, but I have done some of that already and didnt have issues.
Its designed this way. And if you must haul ass up steep stuff in 2 or 4h, still try manually shifting, and get the RPMs to around 3k or better and you will be surprised how much better it does.

Excuse my dramatic thumbnails. Its the nature of the YT beast

Trailer steep climb video:


Redcone:

This is the way…. 99% of the over heating problems solved!

 

[izzy]

My 2025 4 door long bed Off Road Tacoma runs great except... the transmission overheats on slow steep uphill grades. I have to keep the dash view that displays the transmission temp on so I can see how hot it is and shut it down before it hits the red. It happens on steep paved roads with lots of tight turns, where I'm averaging about 15 -20 mph, so power is never an issue. If there was a 2wd low, I'd probably use it but I can't so I have to use 2wd high.

The dealer contacted the factory and they say they know this is a problem but don't have a fix. I am very concerned I'm doing permeant damage by creating varnish, and cooking my trans seals. I am pretty sure my trans wont' fail under warranty but I won't be surprised if it leaks in a few years and needs to be rebuilt in 10 years. I keep my trucks over 20 years and have never previously had a problem with a transmission in over 200K mile.

I believe a serous trans cooler is needed, with an electric fan on a temp switch. The trans should run at about 175°F to 225°F and I think it gets close to 300°F before the over temp switch cuts in and it cuts the engine power. When the engine is warmed up the radiator runs around 190°F to 220°F, keeping the trans fluid that runs through it close to that temp. Since this only happens at low speed when air flow is minimal, I think a fan is necessary. The engine temp is neve a problem so I don't think we need to improve the radiator, I just don't think the heat exchanger in the radiator is large enough to do the job.

The most heat would be removed if the trans cooler was before the radiator, to maximize the heat transfer from the trans fluid to the air, but the greatest reduction in trans fluid temp would be if we put the trans cooler after the radiator. The only concern there is that doing so might keep the trans cooler below the recommended operating temp in cold weather at higher speeds and less challenging terrane.

What you you think?

Are you using S mode and downshifting uphill or leaving the truck in D?

Gotta downshift going uphill to force the converter to lockup and the closer you are to the engines peak power, the less work the torque converter has to do.

These are small engines, you're gonna hear it when going uphill at low speeds where you can't utilize the torque.

 

[TacoFreak]

The dealer contacted the factory and they say they know this is a problem but don't have a fix.

It is interesting that Toyota has finally admitted that this is a problem, particularly since a lot of us have know that for a long time. The next interesting question is will they do anything to fix that or just keep pushing us off until the warranties expire.

 

[Someguysomewhere26]

Did they say anything other then we know about it?

Might be the first case I’ve seen where Toyota said anything at all.

 

[izzy]

The dealer contacted the factory and they say they know this is a problem but don't have a fix.

Did they say this to you in writing or just face 2 face?

If it's not in writing idk. Customer facing communication if it's not in writing doesn't mean much. Service writers be saying anything tbh

 

[Someguysomewhere26]

Darn was hoping they finally said something

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