3rd gen Transmission Cooler Upgrade

Jude curious if someone knows which line on the trans is the feed line and which is the return ?

 

I thought I read some where the top one is the feed and the lower one is the return. When I did mine I had the upper one going to the top of my new cooler and the lower one going to the bottom because I have it mounted sideways. I put a temp probe in there to turn my fan on and when it wasn't turning on I checked the hoses and the one coming out of the bottom was hat and the one on the top was cool so I swapped them. Now the bottom one is going to the top of the new cooler and coming out of the bottom of the cooler and going to the top. This seems to be the opposite of what everyone else is doing but it seemed to me that the hotter one would be the feed.

 

I followed the lines back to the trans and from what I can see it made sense to route my bottom line (which seems to be the feed line) going into the bottom of the new cooler, mine is mounted sideways as well, then the top line of the new cooler goes into the bottom of the old cooler. I suppose it doesn’t matter as long as mounting the cooler sideways will not create an air pocket if that even matters at all. My temp did not go down at all on my normal drive, but I will be able to tell when I tow and the thermostat opens up.

 

That is good to know and I did remove my stock cooler so I'm only running the Hayden 698. I wasn't measuring before I put the new one in so I'm not sure what they were before but on hot days I still reach 200 on the highway. I've been debating on whether or not to put the stock one back in but I think I'm going to wait until spring and then decide.

 

The OE cooler is pretty good quality, it for sure will not hurt and will more than likely cool the fluid off better with both. I’ll update when I tow which should be soon. Highest temp I’ve seen is 241 while towing 5k lbs up the cajon pass here it CA. Outside temp that day was 60 degrees and I’m on 35” tires.

 

that's about the same as my stock cooler (built into rad). doesn't the tacoma actually have a transmission fluid warmer; using engine coolant as a heat exchanger? maybe that's why it's running the same temp no matter what cooler you have...

 

You owe it to yourself to make an effort to understand why you have a transmission thermostat before you go to pinning it in the open position. There is a reason why Toyota engineers installed a thermostat within the transmission in the first place. I assume that their intention was to heat thus thin the transmission fluid quicker to an operating temperature.
Yes heat kills transmissions and the component that causes most of the heat is the torque converter. It causes friction when the engine speed doesn't match the transmission input speed. Keep in mind that the thermostat has a purpose.
I like the idea of monitoring the transmission temperature especially when towing, can't go wrong there.

 

The way you designed your system seems pretty solid, don't know how more solid it can get, and how much more you can ask for it.

This is how I did mine, I wanted something that was totally closed loop and separate from the OBD/ECU, and did not have to rely on Bluetooth APP monitering. So I found some Gauges from Autometer that can trigger a relay based on user programmed set High Point.

My aftermarket Transmission Fluid Gauge I installed has the ability based on a programmable set temperature to control a relay which controls the fan on my trans cooler, all it does is it closes a ground signal to the relay. It's all dummy proof with no switches or user input needed. The Gauge is pretty nifty that the Face starts blinking Red when the set temperature is reached, and after 10-15 -ish seconds the Gauge stays solid red until temps fall below the set.





Weatherproof Relay kit from Frastronix


I also just got done this past weekend of deleting the Factory Clutch Fan and installing a General Motors OEM Factory PWM controlled Spal 18" Electric Fan that's used on Corvettes and Camaros. Goal is to build a overerly built cooling system for the coolant and trans fluid. Pretty sure im getting close to that goal..

 

I agree, I added an additional cooler to keep temps at a factory level with my added weight and tires. I want it to run 180-195 like intended, but I do not want it to get much above 220-230 while towing. Let the thermostat do its job.

 

doesn't it have a transmission warmer? would this explain why some people are getting the same ATF temps even with an external cooler? like this:

 

I didn't know that had guages like that but I did think about adding a trans temp gauge and coolant temp gauge. Right now I have an app to monitor that stuff but it's a pain to have to connect every time. I thought about scanguage too but actual gauges would be nice and look better than a scanguage. I might have to look into that gauge and change some stuff up. I thought about swapping the fan out too but that project will have to wait until spring. I'd be interested to read more on your fan set up.

 

Yes your transmission has a warmer and that is the heat exchange from the engine's radiator. Heat passes from the engine coolant to the transmission fluid provided that the transmission fluid is flowing.
Its hard to beat Toyota engineers.

 

More info on the e fan setup

 

https://www.tacomaworld.com/threads/cooling-issues-not-anymore.682278/

 

I thought that was the one , did you have any issues with the controller

 

It was trying to find enough time to actually do the job..

No troubles with the Controller other than somehow thinking that the Device Setting for the fan was supposed to be on 1. It's all working on 0.

 

When I was running with the stock cooler and thermostat unpinned, I actually found that the transmission heated up slower. After a 20 minute drive to the store the transmission still wasn't warmed up to the point of opening the thermostat, only 150-160*. However when pinned open it comes up to temp much quicker. Logically this is because the radiator/engine heats up to 180* much faster, within the first few minutes of driving. With the thermostat pinned open the trans fluid is then exposed to the 180* radiator which warms up the fluid thus warming up the trans.

 

Not sure if any bigger ones are on sale but Eastwood has this Derale on sale for $22 less than Amazon plus an extra $10 off for being a new customer.

https://www.eastwood.com/derale-plate-fin-trans-cooler-kit-1-2-npt-13614.html

 

That is pretty cool. How did the install go?

 

Haven't done it yet. Hoping to do it before summer comes and I start towing the boat.