Third Gen Transmission Cooler Upgrade

So it turns out Toyota quietly removed the OEM transmission cooler on the later third gens with the tow package. Mine is a 2023 and I had no cooler. Compare it to my buddy's 2017 and he has the OEM cooler on the right hand side. I started to notice some pretty hot temperatures even just driving around town. I'd regularly hit 200+ degrees. Seemed way too hot for light driving under no load. I once hit 240 degrees driving the ridge in southern cal on a hot summer day. And I'd regularly hit 210/220 just freeway driving in 80 degrees.

I added in a Darale 9000 Transmission cooler (Linked here and below). I had my trusty mechanic install it for me as he does excellent work. All in with a fluid flush was about $400. Mechanic said the fluid came out looking good after 30k miles even though it's hit some high temps. I've driven 3k with the cooler now and the truck shifts perfectly and at nice and cool temps. I drove the ridge up to Victorville a few weeks ago when it was 102 degrees out and the transmission hardly saw 200, even when the truck was weighted down with 2000 lbs of stuff & people.

My mechanic did say that my skid plates are likely causing more heat to be trapped up in there. I have the full RCI skid package from front to transfer case. I can see how this would certainly contribute to some higher temps. Just something to keep in mind. Really consider how far back you actually need you skids to go for protection because it is a trade off for heat dissipation. I've also noticed the oil temp and the AT1 temp (which I think is the transmission fluid pan) seem to always be within a few degrees if not the same. So with the cooler transmission temps the oil temps have also gone done. Highly recommend this setup for any heavier third gen that doesn't have the OEM cooler already. If you do have the OEM cooler, it seems to be pretty solid at its job already so don't touch it.

As a side note if you're looking for a GREAT mechanic in the San Diego area, peep the AAMCO on Morena (1430 Morena Blvd, San Diego, CA 92110 / 619-332-1738 ). They've done work for me on multiple vehicles with zero issues and at a fair price. I'd highly recommend them. Sam, the owner, is a solid guy.

Transmission Cooler Link on Summit: https://www.summitracing.com/parts/...Q0kSVYIroufu59n_uRvUq5W8A_aKIr-oaApjPEALw_wcB

Some photos of the install and some before and after temps

 

Thinking of doing an electric fan setup next to replace the OEM belt driven fan, get some better cooling while idling and in stop and go conditions especially during the hot summer months when it's 100+ degrees out. Would LOVE to see anyones setups if they've done this.

 

Keep in mind AT2 is your converter temp, which will fluctuate often and rise whenever the converter is in slip. That temp really doesnt matter unless it stays high for long periods of time. AT1 is your pan temp, thats the one that matters.

For anyone looking for more info, theres a couple threads here that have gone into this extensively.

https://www.tacomaworld.com/threads/3rd-gen-transmission-cooler-upgrade.482280/

https://www.tacomaworld.com/threads...l-toyotas-write-up-with-many-pictures.526283/

 

How is the ATF cooler mounted? Looks like it is hanging off the main radiator?

 

They usually come with a plastic strap type system that you poke though the radiator. It kind of works like a zip tie.

 

that’s what I was thinking, if you truly had 2k pounds of payload no wonder your transmission is cooking payload is only about 1,000 pounds (people and gear and gas and everything else)

 

Does not seem to the best way to mount it.

 

There's gotta be a cleaner way

 

Thats how damn near every aftermarket cooler is shipped (at least that I've seen). It works, it's not ideal as they tend to draw heat from the rad since they are solid against it. Ideally you want a gap between the rad and the cooler. Theres a few that come with brackets, but those are typically sold as vehicle specific packages. Cheaper aftermarket cooling fans are also often shipped with the same "zip tie" type mounting solution.

 

I mounted mine without using those zipties. Just because they come with, doesn't mean you have to use them.

 

You’re unlikely to find anything to help improve anything in this area. Aftermarket fans are extremely rarely an improvement over the stock belt driven fan. OEM designed electric are decent, but typically aftermarket are not.

There was one e-fan kit a few years ago. The fan itself was solid but the controller for it (Lingenfelter) was problematic and eventually the dude who started it all here quit responding to the thread or issues posted.

Also, while I see nothing wrong with adding a cooler, the temp you are focused on is not the temp to focus on. That is the torque converter temp and isn’t really applicable to anything. Fluid coming out of the torque converter will be warm; it hasn’t been cooled yet. As long as AT1 is reasonable, there is nothing to be concerned about.

 

Last time I drove on at CAT scale fully loaded with camping gear, bags, etc (no people) I was at 5,900lbs. Guessing with people in the car that's closer to 6,500. Tacoma GVWR isn't great. But it takes it like a champ. Upgraded the suspension with Old Man Emu heavy weight stuff and it handles it really well. Worth the coin.

@guaco.supreme thank you for clarifying the AT1 vs. AT2 I wasn't sure where the AT2 sensor was. Before the cooler I was seeing AT1 hit 230+ which was concerning. Now It's hardly hit 200 since the cooler was installed.

The cooler is mounted right on the AC condenser, yes @Barsoom. I was told by AAMCO this is the best way to do it, if you put them flush then the fan can pull cool air though it all, and while you drive it can do the same. Versus if there is a gap, it can create a pocket behind the cooler where airflow is hindered. Best to have it flush. So far seems to have had zero effect on the AC or coolant temps. I've seen some setups online that have it set apart with another fan, but that blocks the radiator and condenser from preforming at its best. Having it flush is the move I think. Seems pretty clean to me. I'll attach some photos of other setups I've seen online (as well as a photo of my old temps driving through Bakersfield this past summer pre-cooler).

@BLtheP Thank you for the info on the electric fans. Sounds like I'll stick with the OEM for now. Reliability is the name of the game for sure.


^ The problem I see with these three is that it's blocking flow to the radiator. Creating that pocket of air. I do like the ones with fans for rock crawling/slow driving when you're not getting that air flow, but honestly the fan is just blocking airflow at highway speeds. don't even need the additional fan if you've got the pull of the OEM fan when they're flush.

^This is the OEM one that my buddy has on his 2017 tacoma with 120k miles on it, his fluid came out perfect on his first flush at 100k. OEM one works great. And the low profile really doesn't block air flow to the radiator.


^ Peep the high temps I was mentioning. Bakersfield I-5 on a summer day.

 

I've always read to mount at minimum 1" from the radiator. While they might disrupt airflow some, it won't be significant enough to hinder rad cooling performance.

USRadiator states there must be a gap between, though doesn't explain why, but I've always had it explained to me it's to avoid heat soak.

https://usradiator.com/auxiliary-co...7TDvDbdouU1EqBlymeTLG_NrYKrXwccBNJsWtZs1Pwrdl

Motortrend states "In any event, the expedient practice of attaching an external trans cooler directly to the radiator with zip-ties and no air gap is frowned upon if maximum engine and trans cooling efficiency is the ultimate goal."

Regardless, if it's lowering your temps and not causing issues anywhere else I wouldn't worry about how its mounted.

 

The US Radiator article also assumes the flow to the radiator is always "on".
The Tacoma is thermostatically controlled, and does not open until approximately 195 degrees.
This means the radiator does not help warm cold ATF, because it never sees ATF below 195 degrees... unless the thermostat is pinned open.

As for the gap / no gap discussion, empirical testing is probably required.
Perhaps some guy in Phoenix will make a series of Flush / Gap tests with measurements.

I'm still concerned about how to bleed the air trapped at the top of the cooler after it is first installed.
I figure it might be possible to pre-fill the cooler and bleed the air upside down.
Then pinch off the hoses, mount the cooler and connect the lines.
Unpinch the hoses so only a very small amount of air gets into the cooler as the hoses are connected.

 

I was concerned when I installed mine, but after some research I learned they are a somewhat open system and vented. The system will purge air once it starts moving. I confirmed this when I installed mine as both feed and return lines were empty when I disconnected them.

 

What temp difference can you expect with just a simple thermostat pinning? I've only towed a handful of times with mine but did get some higher than I'd like temps. Was just gonna pin it in the summer.

 

That depends entirely on location and conditions. I say just give it a try and only add an additional cooler if you feel you need it.

 

if you think there is a temp problem which i don't see, why not just get the early style oem cooler?