Transmission cooler missing…I know I know

I installed mine last week. It’s amazing the difference, literally watching the trans temp hit 195 and immediately the thermostat opens and the cooler fluid starts returning to the tranny. It’ll slide down to around 185 and then do it all over again when it hits 195. That’s how the transmission was designed to operate and should. No more 220+ pan temps. Plus my torque converter doesn’t get into the 250’s anymore. It’s been an easy 25-30 deg temp difference on an empty truck not towing with the cooler installed. Will be interesting to see if I can now tow in D without having to go to S4 to keep it from overheating.

 

I had your same opinion too when I first bought the truck.
Mine was higher than 208 on a 78* day too, which is what made my mind up.

 

It's crazy the difference. Mine does pretty much exactly the same thing, but I have noticed it settles right at 185 after it opens.

 

Sadly we’re excited that the truck now operates as it was designed to, it’s not like we added some new aftermarket part, we just returned a designed feature to the truck that Toyota decided to delete!

 

I would not blame Toyota, other Toyota vehicles never lost the transmission cooler. It was the Tundra and the Tacoma, both under the same Chief Engineer, Mike Sweers.
Save money to increase his bonus ??? Who knows

 

That is about right , I tested mine after install on highway going 80 miles an hour and kept TC unlocked to see what I got .
Pan temps never went above 195 .
Normal driving keeping pan between 185 and 187 .
Overall I am happy i installed the cooler and don’t have to keep thinking about this especially towing my heavier travel trailer next spring

 

It is amazing toyota would hire him considering he worked at Chrysler from 86-90... I wouldn't hire a soul from Chrysler from that time period.

 

Here goes…

3 hour drive at 68 mph using cruise control for the entire 165 mile and no stops. Truck was loaded with four people and the bed had about 300 pounds (clothes and miscellaneous stuff).

Pan fluctuated from 203 to 199. After about 1.5 hours the pan stayed at 199 until I got off the exit and when back to 203. On the highway I never saw the TC go above 213.

This is for data points only…not here to disprove or call anyone a liar.

 

I wouldn’t think the transmission would have to work very hard once you reach cruising speed and don’t stop. Maybe just a hill every so often but I’d expect cruising temps while not towing to be low.

 

I concur with this.

I was doing 212 regularly on my 28 mile drive to work - South Houston

after Nic's cooler - 185 avg max of 197.

2020 1794 Stage 2 Harrop. stock wheels and tires.

 

Do you happen to also have air temp from that time?

When its COLD outside I highly doubt my cooler does much.

 

me?

it did not matter. South Houston weather fluctuates immaterially.

and...if it's COLD outside the cooler works better. why would one think otherwise? The thermostat regulates to 185-ish.

 

Because it won't need to open is why.
It would work much better, but doesn't need to use the cooler if it's already below the thermostat's temp to open.
Just like if you ever get out in cold weather and go touch your radiator, its usually hardly warm(in Alaska, it wasn't warm at all). The heatercore was doing all the work.

It's similar in the transmission's case. The pan might be able to project enough heat that the cold air temperatures keep it cool enough.

 

About 45ish

 

it will need to open to dissipate. but only long enough to get back to 185 degrees. cooler weather will cool the liquid better.

Alaska - ain't talking about Alaska.
ain't talking about the engine radiator either.

the trans creates friction. it needs to dissipate the heat. the cooler will work less in cooler temps, but it will work. the trans will be hotter without it.

I guaran-dam-tee it. it's simple math.

now put a trailer on - what's your position?

 

No it wont LOL
You do realize the pan is part of the transmission's cooling system(although not a significant part) that if it stays below 185 it will NEVER need to open.
Again, the trans does create heat... HOWEVER, if the pan is in an environment that is cool enough, it may keep the pan at a cool enough temperature to where the thermostat doesn't need to open and you're just using the heating function of the puck to keep everything at operating temp.

Apparently you really don't understand how radiator systems work or you're just choosing to not read what I am saying.
Engine radiator works EXACTLY the same as a transmission cooler system.

That is why you depin the thermostat in cold weather because the cooler works so well it can cause issues with fluid never reaching operating temperature.

If it is cool enough to where the system doesn't need to be used, IT WONT BE.

I already have a cooler.
I monitor temps. When I am in a cold region, I can go touch the cooler and it isn't being used much because the heat is being sucked out of the pan.

 

Thanks, just curious.
I would be curious what it would be if it was 95 to 100 outside with a similar load.
Mine unloaded during summer was at 218 on the interstate with some rolling hills.

I am curious how mine would do without the cooler in much cooler weather, based on yours I would expect I wouldn't see much beyond 200.

 

you are full of "if's". count 'em.

my trans NEVER stayed below 185 - unloaded. no matter the weather. it was always over 200. even when it was a humid 40 degrees here.

now, it rarely goes past 195

I was keeping the discussion on the trans & not injecting other systems.

I may never understand things as well as you. that's not my point.

point is - the cooler will keep the trans cooler than not having one. in every circumstance.

maybe not Alaska, but nobody lives there right? even fewer work.

 

LOL it's like frozen Texas, what are you talking about?
I don't have enough data for my trans in this truck for a data point in that kind of weather.
My chevy truck would stay at 160 in Alaska, we had to put cardboard in front of the cooler/radiator so it wouldn't gel.

 

I am interested in the summer time temps as well. But unfortunately I have a while to see those numbers…

 

I've been to Alaska once.

agreed - it's damn cold. vehicles should come standard WITHOUT radiators.

landed in deadhorse for a BP gig...never again.

they dressed me like the Michelin man.

 

LOL Yep, VERY cold and VERY dark.
I enjoyed it, wouldn't mind retiring up there at some point.

 

Shit up there we used to cover everything in the front of the radiator with cardboard to block the cold air or your heat didn’t work for shit.

 

Even at 40 deg my cooler will function on long steeper hills but not as often as when it’s warmer. I think that it has to be considered that all of us will have different readings and performance based on where we live too, both temperature and elevation will have major afffects. For example while hot temperature wise, Texas is flat as hell, it’s a higher ascent to my house from town than any hill in Texas with the exception of the Henry’s in W Texas. That’s why I originally said that Toyota could have removed the cooler for trucks sold in flat regions of the country but to sell the 19-21 Tundras in the states out west was a huge disservice to the consumer. It’s like selling a diesel in Alaska with no block heaters, you are certain to have problems. I can overheat the transmission in my truck within 20 miles of my house pulling the camper in D with tow haul on.

 

Im right there with you, my trans never stayed near 185 without the cooler, almost every screen shot I have my trans is well over 200 and just stayed there, even at 32 deg ambient temps. Now it never goes over 195 except for a split second.

 

So if a guy has a '15 SR5 TRD Off Road and wanted to add the sensor for the transmission temperature, where would I look for that part? Is it possible to install it post factory?

 

Any obd reader should work

I use a scanguage 2

 

They leave the factory with two temperature sensors in the transmission. No need to add another one.


The easiest approach is to buy:

$32 Veepeak OBDCheck BLE Bluetooth OBD II Scanner Auto Diagnostic Scan Tool for iOS & Android, Bluetooth 4.0 Car Check Engine Light Code Reader

https://www.amazon.com/Veepeak-OBDCheck-Bluetooth-Diagnostic-Supports/dp/B073XKQQQW?crid=3CV20L2AB1IAI&keywords=veepeak+obd2&qid=1638418247&sprefix=veepea%2Caps%2C162&sr=8-1-spons

Then download OBD Fusion from your App store of choice and pay the extra $10(?) for the Toyota/Lexus PID bundle

 

I just ordered that OBD unit today online.
I see the the coolers kits are a month out anyways, so I am gonna monitor temp for a bit and see what I see.

 

40 pages in (on my settings)...probably a waste of keyboard wear and tear writing this...

As a reference point. I drove my '21 4runner on a 2900 mile trip last three weeks. Rig was heavily loaded with gear and 2 additional people.

The trip was mostly in AZ, NM, CA and parts of W. Texas. Temps were in 60s, 70s.

On flat highway temps never got above 163F. Stop and go traffic temps actually went down to 150s.

In hills temps never got above 190F.

In one extreme section of hills the converter stayed unlocked for almost 45 minutes straight with high engine load and temps only got to 223F at converter, and 203 at pan.

The 4runner has the old school in-tank cooler in radiator with no thermostat. It mimics the pinned Tundra thermostat. I was curious how the system would operate in colder ambients.

Some mornings the temps were in upper 30s and pan temps took forever (about an hour of continuous driving) to get out of 130F range.

So it looks like Toyota has had confidence in the A750 to run with very cool trans temps. Fuel mileage wasn't impacted. over 2900 miles I averaged 19.4 mpg with tons of gear and people and 80 mph highway runs.