Transmission Temperatures

Howdy,

What is the ideal and expected temperature range on Tundra transmission temperatures?

Should I consider upgrading my transmission cooler?

Where IS my transmission cooler?

I just plugged in my Scangauge II that was dialed in for Tacoma and it recognized the TFT code but is running hot hovering around 200° F with minimal stress (5 miles at 40mph flat road) My Tacoma stayed at 150° and only hit 185° when ascending a long steep grade.

If you've not used the Scangauge has 4 options for TFT X-Gauge codes. They are universal to recent Toyotas. If you put in a wrong one you get no reading so doubtful the provide a false reading and you don't input model only engine size. I'll do that today...

I was under the impression transmission fluid is all about the same and heat effects the same with ~220°F creating varnishes and shortening the life of the transmission.

Since I'm getting 200°F with almost no strain in mild weather I'm concerned what will happen when temperatures hit 100°+ and I'm towing long haul.....

Thanks,

Greg

 

What year is your Tundra?
Regards,
bc

 

2019. Brand new

G

 

Starting this model year, there is no cooler as in previous models. I have not been able to get an official explanation of how the cooling works but it appears that the warmer now acts as the cooler as well. Toyota describes it as :"integrated engine/transmission oil cooling". There is no takeoff port for the fluid so adding a cooler would require purchasing the part (about $200), having it installed on your transmission plus a cooler and lines. Cant say how this would affect warranty. I am attempting to get the information from my dealer. The temperatures you list are similar to mine (XGuage and Torque App) as are your concerns. I have towed my UTV/trailer (about 1400#) across the mountains twice and am getting temperatures in the pan around 215 deg. on sustained speeds. Up to 225 going up grades in 4th gear at 55 mph. My 08 model never got over 205 on the same run. Ambient temp around 50 deg. Good luck and stay in touch.
bc

 

What's this loop in front of the radiator?

It's down below... that's the bottom front edge of the radiator to the right of the photo.

I figured trans cooler...

G

 

Power steering cooler.
bc

 

Or maybe condenser.

 

Hmm...

So a mystery.. HAs anyone asked a Toyota mechanic or referenced the official repair manual?

My invoice/MSRP paperwork clearly says trans fluid cooler....

G

 

I have a query into my dealership but no response yet. May visit tomorrow. Unofficial response is " as long as you tow within specified weight limits and service intervals, you are OK". Too OCD to accept that. Does it say cooler or cooling? Subtle difference.
bc

 

Not on the 2019. No fluid leaves the transmission.
bc

 

I’d say a brand new truck on a flat road whatever temp you are seeing is most likely okay for those conditions.

 

My 2018 stays around 195 while driving normal roads at 55. Sometimes it’ll go up to 210 for no reason - no big hills or acceleration, then come back to 190s.

My 2010 would go up to 220 or more while towing, sometimes up to 240. That’s around where the gauge would move up also. 2018 doesn’t have the gauge, but has the cooler with the ac unlike the 2019.

As for adding a cooler, I know some people say “the engineers are smarter than you”, but then why was there a cooler from 07 to 18? Only change was in mid 10 when they added it with the ac. My transmission went out in my 10 and I got a remaunufactured one under warranty. Never ran the same again. I’d rather spend $200-$500 or so and add a cooler.

 

I guess because as long as you are running in the conditions it is engineered for, you are good. Doesn’t hurt but not necessary. I was going to add a catch can but decided not to after some additional research an insight from experts for my mods.

 

What's the deal with the hoses on that round fixture on the side of the transmission...

G

 

Think those run coolant from the engine. Acts as a transmission warmer and I guess cooler for the 2019s.

 

Yep. Previous models had an oil takeoff with thermostat between the case and the warmer. This is how the oil was routed to the cooler. Thermostat opened around 225. On my 08 it opened sooner. You could pin it open for really hot weather or heavy loads. You could also plumb in a bigger cooler. I am researching having one added to mine. Part is around $200.
bc

 

What?!

That doesn't make any sense... They would have to completely redesign the transmission with water galleries to circulate to have any effect. I seriously doubt this is what's going on....

I could see it transferring trans fluid to remote cooler somewhere!

It's so strange as what ever they've done seems to not be as obvious or maybe as efficient as time trusted solutions.

It's real curious they have "hidden" what's going on and making upgrading tricky. I mean there are some who like to take these trucks to the extreme OR limits and a high volume after market cooler de rigeur for any serious off roading...... I'm in Phoenix and it'll be 105°F ++++ real soon.

Can't believe the techs were more concerned with getting the transmission warm instead of cool. Easily could have spec'd a temp gauge and called for extended warm up period....

Still trying to determine which sensor the Scangauge in monitoring....

Part of me is like...not gonna worry about it.. Toyota tech "probably" know more than I do about these. Another is trying to plan for the extremes of towing in the desert...

I plan on keeping this Tundra for the lang haul... not a 3 year trade in..

Thanks!

G

 

its definitely integrated into the condenser. If your looking at the truck engine bay, if you look at the condenser assembly. there are two sets of pipes going to/from it. The ones on the right about midway up are the AC (you know this because one of the lines has an "H" on it foe High Side). On the left more towards the top you will see two additional set of pipes, these are the Tranny (you know this because if you follow those lines through the back you can follow them down to the tranny.

 

An Engineer's smarts only go as far as the money the bean counters allow them to spend. An auxiliary transmission cooler is better, especially in the southern climates. Transmission shop owner in Houston I use stated the first thing he adds to his new trucks is a large transmission cooler if it doesnt have one or the oem is too small.

I monitored my temps as well during summer and it floated between 195 and 220 without towing anything and unloaded. My tahoe stays around 165 and usually around 135 in town (which is probably too cold). Both trucks have tow package. If i start towing with the Tundra like @Krohsis I will follow his install of transmission cooler.

https://www.tundras.com/threads/install-complete-on-additional-transmission-cooler.12385/

 

I guess my issue with this, we all know that Toyota designed and heat tested the truck, and confirmed tow ratings of 10k pounds. They didn't say "10k pounds in Michigan in February and 2k pounds in Georgia in august." they said, 10K pounds, which means that they are confirming that as long as you are under 10k pounds, you should be good with stock. Bean counters also take into account warranty when something breaks that shouldn't. Sometimes people looking to mod, install a solution looking for a problem.

 

Not on the 2019, at least none I have looked at.
bc

 

I couldn't believe this...I had to research... the 2019 condenser assembly is a different number that shows only fitment for 2019. But to make things more complicated, the transmission is exactly the same between for all 2014+ tundras, which means the ports are there, so where do they go? someone with a 2019 needs to chime in here and see where these lines go, as these are the ATC cooler lines on my 17 Pro, they are on the left of the radiator/condenser as you face the truck (leaning over the bumper to take the pic

 

I would normally agree especially if you follow severe service maintenance and keep the oil fresh, except it seems Toyota made incremental changes to this system and, at least in my opinion, only to save money not necessarily extend/maintain system performance, but who knows. They started with fully seperated transmission cooler, then an integrated cooler, and now no cooler. The question is why. Is it a better design, are the higher temps better for longevity or mpg.

Now the big question... Did Toyota remove the drivers side grab handle from 2014+ purely to score higher on small overlap crash test or to save a few bucks. They just got burned on the passenger side and the grab handle contributed to the lower rating? Things that make you go hmmmmm.

 

The truck has a heat exchanger. My truck usually runs close to coolant temp when unloaded. When towing up a grade it will go up about 10 -20 higher then than coolant temp.

 

That is the same setup I have in 2018, looks like 2019 they eliminated the transmission fluid running to the radiator for heat exchange.

 

there has to be something, every vehicle has some sort of tranny cooler, you have to cool the fluid down regardless if its a tundra or a Yaris, inside the tranny it won't cool by itself, especially since the 2019 still has the same tow rating. Plus the engine/tranny are the same, so the ports are there, so someone here is lurking with a 2019 and they need to post an engine pic like mine above to see where the tranny cooler lines go to. I read somewhere that for 2019 it might be an engine oil/tranny cooler instead of condenser..but don't know till someone posts a pic...

 

https://tundraheadquarters.com/documents/tundra-transmission-fluid-flush-tsb.pdf

There is a pic of it on page 3. The thermostat for ones with a tow package is next to the "ATF warmer".

 

I have a 2019. There are only the coolant lines going to the warmer on the passenger side. Previously there was an oil takeoff with a thermostat between the trans case and the warmer. See: https://parts.toyotaofcoolsprings.c...kcmEmeT0yMDE4JnQ9bGltaXRlZCZlPTUtN2wtdjgtZ2Fz
With this part missing, you cannot add an aftermarket cooler.

 

the heat exchanger is on the side of the trans, there are coolant lines that run to it. 2009 was the last year that had a cooler in front of the radiator.

 

yes but up to 2018 (apparently, still questioning it) the tranny cooler was integrated into the condenser, I have a picture of it up above.