19' and 20' No Trans Cooler

I know that Toyota dropped the trans cooler on front of the rad and went strictly with the coolant trans cooler for the 19' and 20' Tundras. Has anyone that tows a trailer with the new setup ever have an overheat issue? I plan to tow my 5K trailer this summer with my 2020 Tundra. I'm trying to create a thread dedicated to sharing your towing experiences with the '19 and '20 Tundra's to find out if running without an air trans cooler is an issue. Please post you experience, what you were towing, payload number if you know it, any modifications that could contribute to the problem (over sized tires, light bars that could stop air flow, grill mods) and environmental conditions such as elevation, grade and ambient temperatures. Please post your temperature readings and how your monitoring them.

Moderators, can I request that this be made a sticky?

Thanks

 

Does your 2020 tundra have a trans temp gauge? My 2019 tundra does not, so I just ordered and installed a scan gauge so that I can monitor it this summer while towing my camper. Im not sure if the truck would display a message if it overheated or not.

 

I coulda swore the new tundras had the trans cooler for the tow package built into the a/c condensor.. I’ll have to check the next one I get at work..

 

https://www.tundras.com/threads/2019-external-transmission-cooler.54991/

https://www.tundras.com/threads/2019-5-7-trans-cooler-location.33216/

Some people are reporting higher #s than pre-19s. The gauge went away years ago as it didn’t really do anything but sit in the middle. I’m sure there is an overheat light that comes on if you get too hot. There’s also someone attempting to retrofit the cooler on his 19/20.

 

After looking in my owners manual, the truck will display a warning message if the transmission fluid gets too hot, but doesnt mention anything at what temperature the warning is displayed. I towed my camper 6 times last summer with no overheating. I belive my camper weighs in at 6500 pounds.

 

You can count on it going off at about 285, which of course, is TOO LATE. Hence you'd better monitor temps live with your favorite tool. IMHO under NO condition, I don't care if its 110 outside, stop/go, hills and mountain passes while towing trans temps should remain 200 or less, call me old fashioned...

Luck and enjoy those Toyotas. : ^ ))))

 

The same day I installed my scan gauge I was out doing some "spirited driving" and managed to see 226 degrees in the torque converter, while coolant temps never went above 193 degrees.

 

This thread is going down the same path as those other 2. There’s over 500 posts regarding this already.

Trans light came on in my 2010 around 245-250. Not sure about newer models. Toyota uses this new synthetic or WS or whatever it is fluid which can go above 200. That diagram on the internet saying 200 is death for transmissions is very old.

https://www.tundras.com/threads/2019-external-transmission-cooler.54991/

https://www.tundras.com/threads/2019-5-7-trans-cooler-location.33216/

 

I dont believe 200F is going to kill the transmission. My 2020 running around town in 70° temps sees a constant 200F for trans fluid which is exactly the same as my coolant temps.

 

Yeah i gotta get used to that WS concept and thanks for the reminder of previous nauseatingly repeated same topic posts. not trying to incite over 200 riots yet I still don't like it, just an opinion. But I will flush the mother w/WS every 3rd wicked central Texas summer (can be 90+ days of 100+ degrees here where it's above 100 each day for 8+ hours, yeah ouch) year, if nothing else to sleep better about it.

Luck and enjoy those Toyotas. : ^ )))

 

I’m towing 6500-7000 all the time with my 2019 SR5... no lights yet. Then again, it’s a 2 year lease so I don’t care enough to monitor the temp other than watching for the idiot light. I’ve maxed out my 2017 a few times and never had any issues either, but that has the more robust cooling system I guess.

 

200 isn’t horrible. 220 is where I’d be afraid to be. 180 is technically the ideal trans temp and engine temp

 

That the thing, your never going to see 180 if the coolant temp is at a normal 200. The '19 and '20 use the engine coolant to cool and warm the transmission.

Your right in that trans fluid degrades quickly after 225.

 

Both of those threads are just bitching about the missing trans cooler but really never addressed the issue that it really matters. This thread is asking had anyone had a trans overheat on the '19 and '20 trucks? Is there really any problem with cooling the trans with the engine coolant exchanger?

 

This is dead on. From what I've read, 200-220 was probably the target operating range pre-2019. Full synthetic fluid could postpone fluid degradation to above 240 degrees.

Not at all...IF the engine coolant exchanger had enough heat transfer area to get the job done with 195 degree cooling medium (small Delta T). The warmer/cooler on the transmission would probably need to be the size of a milk jug. Fitting it on the transmission would be challenging this late in the Gen3/5.7L cycle.

 

Nope.

 

Adding an auxiliary cooler after the factory one should be do able with 18 parts and would likely drop the temp to around 180. But I can say those engine coolant trans coolers do typically work pretty well

 

The ws fluid is supposedly synthetic.
But it does degrade pretty bad after 220, doesnt like high temps

 

I guess it comes down to is there a real problem running a trans at temps between 200 and 225? Your natural instinct is that the cooler the better. Engines use to run at 180 and temps have steadily increase to were 200 is normal and result in the best fuel mileage and emissions with no effect on longevity. Would this hold true for the transmission? Has anyone had their transmission overheat light come on frequently on the '19 and '20 trucks pulling heavy loads in high ambient temperatures?

 

I guess if you’re going to be running the transmission hotter, either the internals (seals, solenoids, bearings, etc) were always designed to take more heat or they put new parts in there. IMO, there’s a big difference between running 180ish all the time to running 230ish all the time with spikes in hills / heavy loads / etc. Anyone check to see if the internal part numbers are different for the ‘19-‘20 transmissions? If not, someone thinks the parts in there now are over engineered. Hopefully it’s the engineers and not the bean counters making that determination. As I said, I’m towing the hell out of my 2019 and no overheat lights yet. I suppose we won’t know for many years whether the failure rate increases.

 

Some have expressed skepticism that WS is a full synthetic, and the internet is awash with "it came out black" stories at 60-80K miles, some on passenger cars. My belief is if you run it above 220, it's will quickly turn black. I've read here, on BITOG, and other Toyota forums that WS is at best a synthetic blend, but you know what they say about the internet.

I have looked up the MSDS/product spec sheets for both Toyota WS and an advertised full synthetic (See below). Assuming the products' behavior between degradation start and their flash point (where product actually starts to burn) is more or less linear for both products, the MSDS flash point may provide some insight into product capability; i.e. full synthetic...or not. Sort of like extrapolating the temperature data back from flash point to where degradation begins.

https://cdn.website-editor.net/6622da50fd3744b3b1560a41005a6921/files/uploaded/00289-ATFWS.pdf

https://attachments.priuschat.com/attachment-files/2017/08/131427_US_VAL_ML_ATF_EN.pdf


For Toyota WS (ExxonMobil did make it for them at some point), the flash point is 347 degrees F; for Valvoline MaxLife, the known full synthetic, the flash point is approximately 395-400 degrees. I don't think MaxLife has 50 deg additional temp resistance to degradation (maybe 20-40), but it is taking the full synthetic 50 deg longer to burst into flame. One of the guys here (claim your credit) contacted Valvoline Tech Service about MaxLife degradation, and he was told that degradation will begin around 240 deg and that the rate of degradation will accelerate quickly as temperatures increase. My thought is WS ain't no full synthetic, and additional temperature resistance could be had with another ATF.

 

We put max life in trucks all the time with no I’ll effect.
The ws typically is black writhing 20k even in the cars. I have tons of the stuff so I do a drain and fill every oil
Change. Once I’m out I’m going amsoil most likely.

 

Perhaps I’m being nieve to think Toyota is beyond short term thinking leading to profits, as I bought the ancient Tundra over the tech savvy Big 3 for the fact it was built like a brick shithouse.

That said if the trans fails prematurely, I’m going to lease domestic every 3 years from now on and treat the truck like a toaster...a throw away appliance.

I hope this was an engineering update based on the fluid and the engine trans exchanger that will still allow our trans to last 250k miles without issue...

 

The transmissions are pretty stout even with the fluid issues. Plenty tundras running around on original fluid at 200+k

 

I'm kinda worried mine might be running to cold, takes forever to warm up.

 

Im not going to say you haven’t completely read through those other 2 threads, but I have and I’m seeing the same comments. Temp (overheat), adding a cooler like 18s and prior, discussing the effectiveness of the 19/20 “cooler”.

I’m also not telling you not to start a new thread. It’s not my message board. I was just trying to be helpful and say this has all been discussed in depth and give you stuff to read to answer your question.

There’s not much more that can be said. -19/20s don’t have a cooler in the same style as prior years.
-No one knows why for sure.
-So far no known failures, but maybe they aren’t old enough to have failed yet.
-It’s potentially possible to retrofit a cooler if you buy the prior years parts.
-Some reported higher temps than prior years

 

Can you link me to the thread where someone had an overheated trans on the '19 and '20. There are a pile of posts and I read quite a few but never saw a post about an overheat (I'm not doubting you). I just thought it would be easier to follow a thread dedicated to the problem if there is one. The other thread just went into how to retrofit the '19 and '20 but no real evidence of a overheat that I came across.

 

I’ll look for it. It was in one of the threads somewhere where someone said they were running hot. Not overheat, but I think if someone was consistently we would hear about it.

It is good to have a thread just for temps but it’s starting to turn in to the same posts. Was just trying to give more to read on it.

 

I've been trying to steer it to a trans temp thread relating only to the '19 and '20.

 

One guy had a temp warning backing a trailer uphill.

That's about it.