ATF cooler install- fluid levels?

Hello all,

I am installing an ATF cooler on my 2015 tacoma and I've been confused about one thing, fluid levels.

I bought the truck used so I don't know what type of fluid is in there now so I assume a full flush will be needed? Even still am I adjusting the levels with the cooler manually filled up? Not filled up? Do I pin the transmission so it's constantly running through the cooler?

Literally every writeup I've seen, and I'm pretty sure I've seen every one the internet has to offer, not a single mention of any of this. Just install and go? That can't possibly be right...please help I've owned the cooler for weeks and it's just sitting around because of this.

 

You add the extra volume to fill the cooler then do a temperature check.



https://www.tacomaworld.com/threads/how-to-drain-refill-automatic-transmission.63851/

 

Should run out of radiator into cooler then transmission for most cooling. I think mine took about 4.6 quarts with my cooler. It's Toyota WS fluid also and Aisin WS works fine too. Same thing but cheaper.

 

If you didn't get a manual you can probably find one on eBay for reference and saves headache over simple stuff.

 

In simple terms, you install the cooler. It will most likely install in the return line from oem trans cooling setup, that heads back to the transmission pan.

Once installed, you will need to add fluid until properly filled. If you do not know the history of the existing fluid, probably best to do a complete flush and fill BEFORE attaching the return hose back to the trans pan.

Regarding a trans cooler install, I did this many years ago on my 2010 DCLB Prerunner. I live in a warmer climate, so I decided that no trans fluid would enter the radiator. My cooler is adequately large for summer driving.

The oem aux trans cooler for the oem towing package became a power steering fluid cooler.

As for trans fluid, my truck has been driven the majority of its miles on Mobil 1 ATF, not the crappy WS fluid.

 

I always run my cooler between radiator cooler and transmission for the best cooling. I didn't know Mobil made trans fluid that would work. WS is like water with no viscosity film at all but I definitely would not flush with high mileage. Not at all if serviced regular. I did buy a steering cooler and I used Lucas synthetic fluid. I guess I will use it even though fluid is is easy to change. I thought it might help preserve seals longer. WS is like water when I wiped it up. Must be environmentally friendly. I use Mobil 1 in everything else but haven't seen their fluid. Did your prerunner come with auxiliary transmission cooler besides the radiator transmission cooler? I'm going to get one of those aluminum radiators next. A little more than factory but bigger channels and bolts up to everything. I know it's just a matter of time before the plastic one goes. $388 Toyota and $425 CSF all aluminum. Only issue I have is I would want it through radiator in hot climate. Coolant still cooler than natural transmission temperature operating temperature. Better to maintain consistency that swinging up and down. Hey if it works for you and no issues then you know already.

 

If you want to do a "full flush" without dropping the pan, now is the time to do it, while you have the send line open.

Remember: Always crack your fill port before draining any fluid, so you know you have a way to put it back in!

While you're installing the cooler there will be a point where the loop is open and the cooler hoses haven't gone on yet. Attach the hose that goes from the transmission to the bottom of the radiator, and then start the truck and collect as much as it will give you, then turn the truck off. Complete the installation, and then take note of how much you removed from the trans. This number is going to be a rough guide for how much to now add - remember, you have to add more to account for the new hoses and cooler internal volume. If you want to be really precise and maybe save having to crack a whole bottle of ATF for a couple ounces, attach the hoses to the new cooler, plug one of them, and fill the whole thing with ATF to get the volume, then put the still new transmission fluid back into the bottle.

Whether you're trying to be precise or not, now that the installation is completed, add the new transmission fluid to the transmission, and complete the standard transmission level check procedures (too lazy to link, they are linked in the DIY Maintenance sticky).

Now check for leaks and keep an eye on them for a little while to make sure the install went well.

If you want some transmission cooler hardlines and 90* fittings (these are what go from your trans to the first set of factory style cooler lines) I have some NIB Toyota factory parts that you can have for the cost of shipping.

 

You check the level with the truck running and trans fluid up to temp.
The fluid will be circulating in the system at that point.
It pulls fluid FROM the pan and INTO the cooler. So the pan will be low.
And you check the level at the pan, so just do it like the manual says and add it until it trickles out. READ THE STEPS IN THE LINK BELOW.

I'd just buy WS fluid and add it. But you can do a flush since the hoses will be off.

Manual says - DIY - It's a pain in the ass.
https://www.tacomaworld.com/threads/how-to-drain-refill-automatic-transmission.63851/

Flush - https://www.tacomaworld.com/threads/diy-full-flush-for-automatic-transmission.68462/

 

fluid level check procedure and enough fluid to compensate for the added volume of the cooler.

 

To clarify a few items you mentioned. In regards to my Prerunner and the transmission cooler, from well before installing the trans cooler, temps are monitored via a Scangage. Knowing the trans fluid temp within the pan typically runs at 160*f, that temp is far below the coolant temp of 188*f. Granted, the trans fluid temp may come out of the transmission at a temp above the 188*f of the engine coolant in the radiator, but ultimately the cooled trans fluid is cooled more than the oem design.

You mentioned temp swings of the fluid, actually, the fluid temp, per the Scangage remains between 158*f and 164*f, and stabilizes at 160*f. In the most extreme cases, the trans fluid temp was in the mid 170s, and quickly dropped to normal once airflow over the cooler increased.

If I were hardcore off roading, the setup would be changed to include a dedicated trans cooler fan.

Yes, my Prerunner came with the tow package that does have the Toyota trans cooler. As mentioned, that small oem trans cooler is no longer used for trans fluid, rather it became the cooler for the power steering fluid.

My truck also has the all aluminum CSF radiator. The original radiator was replaced after a supposed thermostat upgrade made the truck run much hotter. After replacing the oem radiator with the CSF, temps were the same, so out came the aftermarket billet thermostat housing and thermostat. With oem thermostat housing and thermostat, all temps returned to normal.

In regards to the Mobil 1, it is not WS rated. The Mobil 1 is Dexron rated. Prior to WS, the earlier trucks used type IV fluid or something like that. Same trans, but the newer WS is used in the newer trucks. Got about 80,000 miles using Mobil 1 atf, due to get a full flush and service again, try and go about 30,000 miles on the atf fluid.

 

Okay, I know it's a newbie question...but, I'm a new Tacoma owner as of a week ago. I have a 2013 Pre Runner without the tow package. I have a trans cooler that never got installed on my last truck and I'd love to install it on this one since it only has 49,000 miles. I did find the trans cooler on the side of the radiator. But, what is the flow direction? I want to route the fluid from the rad cooler to the aux cooler. And thanks!

 

Try this.

https://www.etrailer.com/faq-about-engine-transmission-coolers.aspx

 

Thanks, I also found info in the tranny "flush" thread that helps out.

 

This picture always helped me for determining which hose to pull for transmission flush, I have the tow package.