2024 Transmission getting HOT in 4x4 climbing hills, skidplates?

Howdy, Got my new 2024 non-hybrid 1794 TRD 3' lift out to the ranch this weekend for the first time. Was so excited, but now I'm super disappointed. The truck can't handle it apparently. This is a property I lease for hunting and it's super steep and mountainous. I'm talking 5000' of elevation gain from valley floor to top. Roads are well maintained but dirt and require 4x4 in most places. Nothing is terribly steep. 4L is rarely required and if it is, only for a short section. Mind you I bought and equipped this truck specifically for the time I spend on this ranch. It has the full set of Talon's garage full underside skidplates for protection.

So this weekend I head up a road I've travelled hundreds of times in different vehicles (Jeeps, F150's, Dodge 2500 and most recently, a 4Runner). The route climbs about 2500' in about 3 miles. Nothing super steep, just a slow steady climb. I operate the truck with the tow gauges displayed on the right side. Half way up the hill I could tell the trans temp was running warm. I stopped and it cooled down. Kept going to my glassing spot for the evening. Had to stop again to let it cool. I've NEVER had to do this in any other vehicle. By the time I climbed up onto my knob, the gauge was just barely touching the red and it scared the hell out of me. I've been doing this my whole life and am in no imaginable way new to 4x4. Hunting is my life and I use 4x4 regularly. I've driven this route way too many times to count and drove the mild mannered way I always have in every other vehicle. The only thing new is this Tundra. No lights or check engine came on, and the gauge only got that hot for a few moments.

I can't imagine this is normal. Has anyone else run their trucks in similar 4x4 conditions (long slow climb) and seen the trans temps top out the gauge? This is not acceptable. I have a couple theories... Either my cooling fan is not coming on? Hard to tell over the roar of the engine (man it's loud). The fan is coming on too late? Or are my Talon's Garage skidplates locking in excess heat and not allowing the trans to air cool? Thoughts?

I shudder at the wasted time taking it into the dealer as there are no 4x4 long hill climbs around and they will never be able to replicate the scenario. Around town and on highway it never goes beyond halfway up the gauge. But if I do take it in, what specifically should I ask them to test for since they will not be able to drive it in the same manner that creates the problem?

 

I don't have a 3rd Gen, but I believe some members here were having similar overheating problems running it too slow in 4- HI. I'm sure others will chime in.

 

Thanks. Hopefully there's a fix for it. It's definitely a slow speed, lack of air flow situation.

 

4lo, my 150 was the same on the beach. 4lo takes the stress off the torque converter.
If your just lolly hanging along on the flats no problem, other than that 4 lo is necessary.

"
“4H” (high speed position,
four-wheel drive)
Use this for driving only on tracks
that permit the tires slide, like offroad,
icy or snow-covered roads.
This position provides greater traction
than two-wheel drive.
The “4H” indicator will come on.
“4L” (low speed position,
four-wheel drive)
Use this for maximum power and
traction. Use “4L” for climbing or
driving, and hard pulling in sand,
mud or deep snow.
The “4L” indicator will come on"

I wonder if tow haul mode would stiffin up the torque converter as these trucks are pretty hi stall.

 

4lo is the fix as these tundra have a pretty hi stall torque converter. Maybe tow haul would help but 4 lo will definitely fix it.

 

Correct and backing up steep incline if I remeber correctly.

 

This is also a good time to point out that the addition of a real transmission cooler wouldn’t hurt either.

 

I have a really hard time buying this being a 4H vs 4L issue. I've owned nothing but 4wd vehicles my entire life and have used them regularly for a few decades. I know when to use H or Lo. I can't imagine having to do this drive in 4L all the time. It's just not that steep. It's a long gradual climb. Again, I've done it hundreds of time in other vehicles and have never once thought of running in 4L. 4L would have me revved up way too high and going frustratingly slow. I literally can't imagine using 4L and being restrained by such low gearing.

 

3rd gens don't really have a dedicated transmission cooler it’s heat exchanger is part of the engine radiator so at slow speed and high load on torque converter will get the transmission fluid pretty hot. Your other trucks might’ve had a better cooler but it’s no big deal you can easily plumb in a transmission cooler on the front passenger side grille area the stock transmission cooler lines are located there as well you just gotta bypass the oem cooler. 4Lo would also help with the temps.

 

Really, why? How is a low stall torque converter an advantage for trucks designed to haul and operate under load? Wouldn't it locking up earlier reduce friction/heat? I need a technical explanation of what makes this truck's tranny so different than my previous vehicles, including Toyotas.

 

The Tundra doesn’t have a real transmission cooler.

Is your engine also overheating? Probably not because it’s got a big old radiator to cool the engine down and it only needs maybe 5+ MPH of airflow over it to cool the engine.

The transmission “cooler” doesn’t utilize a radiator on these trucks it’s a puny little pass through cooling plate or some shit that uses main radiator coolant that is already pretty warm.

The older Tundras that were outfitted to actually do work have honest transmission coolers that run transmission fluid through a stand alone liquid to air radiator. Just like the main engine radiator it only takes a little bit of airflow for that transmission cooler to be plenty effective.

 

Dude it’s a 10 speed direct shift transmission. It’s designed to be locked as often as possible for fuel economy. Plus it’s pretty compact for a 10 speed.

It needs all the help it can get. Buy and install a real transmission cooler.

 

Really, on a $75,000 truck, you have to add an aftermarket tranny cooler to get it to work as it should have all along? That's frustrating. Again, I'm not towing anything. The truck was unloaded. I can't even imagine having to tow something slowly up a grade with this truck after this experience.

 

Sell it off. Or fix the issues yourself.

The 3rd Gen is currently 1/2 baked.

Maybe the mid cycle refresh will address the shortcomings.

 

Please explain to me how this "10 speed Direct Drive" differs from other vehicles I've owned. My 2017 4Runner for example. Other than just having 5 more speeds.

 

I would really love to chat with someone directly who has had this issue. Especially if they've found a fix. Other than installing an aftermarket cooler.

 

Well for one difference your 10 speed overheats easily, where the 5 speed didn’t…

LOL. Low hanging fruit.

 

Ok, I chuckled, but that hurt a little.

 

You could try to use manual mode and keep the truck in lower gears to take advantage of the increased wheel torque without needing to go in and out of 4Lo.

 

No the engine itself never got hot. Never moved beyond the normal mid way mark.

 

It is pretty frustrating the Toyota decided to omit the real transmission cooler from Tundra’s starting with the 2.5 Gen around 2017-2018 or so.

You don’t hear stories about those trucks having transmission heat issues very often.

 

What are the temps that are concerning? Did the AT overheat light come on?

 

@SDHNTR Been all over in my ‘21. We’ve been off-roading a lot, done countless forest service roads while being fully loaded and then some. Did Imogene Pass a few years ago.

Any slower moving inclined paths with loose rock or lots of washouts, I’m in 4Lo and worry free.

4Lo will solve all your problems. Your truck has 4Lo. Use it.

Signed,
A guy who was too hard on his 2012 4Runner (that had no dedicated external trans cooler, by the way) and got the torque converter to start slipping at 131k miles.

 

I went with this option. I also drain/fill my transmission every 30k miles.

No problems at all

 

2018 I believe.

Toyota tells me its perfectly normal for my transmission to hit 250+ on the freeway.

Part of me wants to believe in advances in fluids make this ok.

The other part of me purchased a transmission cooler to add on to my 2020 since its somewhat easy.

 

What are your trans temps running now?

 

My pan temps track engine coolant temps within a few degrees. If I’m just leisurely commuting on the highway, it takes a very long time to even get hot enough to open the thermostat. It opens at 190-195°F.

This is from one of our cross-country trips where I was a couple hundred pounds over payload. Not sure what Fusion is using to calculate engine oil temp…


Prior to adding the cooler, I could get to 225°F+ just cruising unloaded through Tennessee hills.