Transmission running hot, part 2 and update - final verdict

Looks like the only real fix is to add an after market transmission cooler

 

Perhaps, but shouldn’t be required for a brand new truck, under warranty, and when not taxing anything.

 

I understand what you're saying, but I see no point. The dealer won't do anything except tell me it's normal. I'd rather just add a trans cooler to know it's getting done right. These people still haven't given me a 2nd key fob in over 6 months, I sure as hell ain't gonna trust them on the cooling of my transmission.

 

I have a real hard time, after what these trucks cost, having to add something to make them work as they should in the first place. I’m also not willing to let Toyota off that easy. I’m going to continue to make a stink until they recognize the problem and offer a solution. I wish others would too. There’s more power in numbers and that’s the only way we’re going to get anything done.

 

Well Toyota finally closed my case. With zero resolution. The lousy answers to my questions were:

1: the transmission reads temps from “multiple sources” to determine the readout in the gauge.

2: Unable to answer

3: Unable to answer. Even when pressed and a second attempt at an answer was requested, they could not tell me what temp was dangerous.

And lastly, they stated this advanced team read my file again and determined everything was normal and operating as designed.

This was all a total waste of time and I expressed my extreme dissatisfaction. In what world could it be determined that an unloaded vehicle under mild conditions with a redlined temp gauge is “normal”? I’m beyond pissed off.

 

I would get an obd reader to actually see the tran and tc temps, but understand your frustrations.

 

I did. See other post. Seen pan temps as high as 223. Whether that’s excessive or not according to Toyota, we’ll never know.

 

Sorry we’re all dealing with this, but see above, I called it. My friend and Dad have owned Toyotas for years, and no matter the issue, they were always told it’s normal.

My buddy had a 2013 Tacoma with a 4 liter that sounded like a rattle can upon acceleration. That was deemed normal by Toyota.

My Dad had the driveshaft issue on his 2003 GX470, that was also deemed normal. Oddly enough, they came out with a fix 5 years later for a “normal” thing.

 

The whole engine is running at 200 degrees (195-205) 223 is not an excessive tran temperature. I added a after market tranny cooler because the puck system is not an efficient way of removing heat from the transmission, not sure how the third gens do it, but prob the same if ppl are recommending a cooler.

 

Have you considered the possibility that your truck is operating normally? It never gave a warning light or an overheating message, right?

 

Yes. Perhaps what Toyota calls normal, But not what any sensible person would call normal.

and I’m even more upset that Toyota couldn’t answer the simple question of how hot is too hot?

 

I don’t know Toyota’s design criteria for this units temperature at all but in college transmission class we were told to aim for 225° when towing or under load. Above 240° was the max where extended service life could be affected. Granted, this was years ago and fluids have changed tremendously. But rubber and silicone seals and gaskets have not and they are what suffer in extreme heat.

 

That is good info, but is that temperature measured in the pan? Because the heat in the torque converter is much greater, correct? And we have no way of measuring our TC temperature.

 

What actual temp did it get up to in °F?

 

223 in the pan.

I have even seen the gauge on the dash hit the red line at much less.

and if I get to 223 in the pan unloaded, what does that mean my torque converter is at? Way higher, right? And what would happen if I were actually towing a load? Isn’t this thing tow rated to 12000 lbs? Laughable!

 

Look, if Toyota could’ve actually offered a logical explanation For all this, backed by mechanical reasoning, I could totally accept the everything is normal explanation. Yet they cannot, so it’s a tough pill to swallow.

 

doubt they checked the bypass valve on the transmission, or maybe they did. The bypass valve opens and closes based on the transmission fluid temperature. The range of operation is 195 degrees (begin to open) to 200 degrees (fully open). If the valve is faulty (fails to open or opens at a higher temp) the temps of the transmission fluid can only go one way - UP. Maybe your valve is bad?

 

Yes, the torque converter generates heat when unlocked. If I’m doing work, mine is generally 10-25ºF warmer than the pan.

This whole thing seems pretty simple to me:

1. Your truck has systems in it that will tell you when it is overheated.
2. Your temps have not been hot enough to actually trigger said system.
3. Therefore, you were never overheated.

Just do a drain and fill every 30k miles if you’re worried. Your truck isn’t worried. It will tell you when it’s worried.

 

Mine has hit 235. Full disclosure. Ambient temp 102 and I drive it spiritedly. JB4 set to Map 3.

Usually it sits around 208 to 225 when I drive it gingerly…

Hopefully the fellas come up with a solution for these temps.

 

Now I’m curious to get under there and see if it’s the same type of bypass valve the 3rd Gen Taco had. It was easy to depress the valve pin with your finger and lock it open with a paper clip. (( had to do this when setting the fluid fill level on the trans ))

 

That is what I am hoping to see. If that is the case I'd say issues solved based on my Gen3 Taco solution/experience.

 

Sorry if I missed it but is this just the gauge reading hot or do you get a pop up warning? Twice now in my truck I've gotten a pop up telling me the Trans fluid temp was running hot and to pull over and let it cool. This happened first in 4Hi on logging roads heading up a mountain and the second time in 2wd on pavement heading up a mountain with numerous switchbacks.

Not sure if this is just the truck or if its a real problem. In the past i've had an F250, F150 and a Durango for work and they all worked fine with no alarm. Both Fords had trans temp gauges and didnt really move much.

2024 SR5 Crewmax with canopy and loaded with tools.

 

What does the Gen 3 owner manual recommend for transmission fluid changes for severe duty?

I believe the previous gen was 60,000 miles. This may be why Toyota isn't worried. Even at those temps, if you change it out often, no issue.

I do get that this is unloaded.

Edit: I just looked it up online....

every 30,000 miles

2018 Toyota Tundra transmission fluid changes are extremely risky to keep your vehicle's transmission congenial and lubricated. If you don't routinely change your fluids at least every 30,000 miles or so, you may find that your 2018 Toyota Tundra transmission will slip.

https://www.stonecresttoyota.com/20...risky to,Toyota Tundra transmission will slip.

 

Yikes, didn't know this for the 3rd Gen either. This explains why they aren't concerned about the temperature.

30,000 miles

2023 Toyota Tundra transmission fluid changes are exceptionally essential to keep your vehicle's transmission cool and lubricated. If you don't routinely and constantly change your fluids at least every 30,000 miles or so, you may find that your 2023 Toyota Tundra transmission will promptly slip.

https://www.coggintoyota.com/2023-toyota-tundra-transmission.htm#:~:text=2023 Toyota Tundra transmission fluid changes are exceptionally essential to,Tundra transmission will promptly slip.

 

Welcome to the new Tundra! Don’t you love it? (Sarcasm meter pegged)

No I have never gotten any warning pop-ups because I always pull over and let it cool before it gets to that point, but it will certainly reach the red line on the gauge very easily on mountain roads at slow speed.

The bottom line is, Toyota designed this truck to haul your kids to soccer practice, not to be actually used for truck things.

 

Not an issue - added an external transmission cooler. Run sub 190 towing and even lower when not towing. Doing all the truck things you want to do and none of the BS those unwilling to simply add an external cooler experience. Pre cooler install the temps were too extreme - yes 220's towing and 210 daily use. Monitor with a SGII. Pan Temp is all you get not converter.

 

Wrong. The fact that you have to add something aftermarket to make a truck work the way it should all along is the very obvious definition of there being an “issue”.

 

Duh. Welcome to the present. The past is the past. Not even duct tape can fix stupid. Happy to add you to the ignore list.

 

I'm confused on your quote of a quote.

I gathered that he was aware of an issue.

Am I wrong?

 

Only you can make that call.

If the OP is an "issue" and nothing more then it is no more than a complaint. Never to be resolved. If the "issue" is a "problem" then it has a solution. Solutions have been presented. Since the OP seems to be unwilling to accept a "solution" he is just another unhappy "issue" complainer and will have to live with the consequences of the purchase decision. Call it what you want. Sell it or stop complaining - buy a RAM equal and be happy. Life is to short for less.