Can a transmission cooler be too large?

[clinebarger]

To answer the question: yes, a cooler can be too big. Why? Transmission are designed to perform optimally when the transmission is within a specific operating temperature range.

The range is pretty wide usually even on Linear Solenoid, Clutch Volume Learning/Adaptive units....Ford & GM 6/8/10 speeds, ZF 6HP & 8HP, Aisin 6 & 8 speeds etc.

150°F to 200°F is good target for most automatic transmissions.

 

[edyvw]

@edyvw Not sure if you have seen this, but this bracket has been made for Tundra and Sequoia that lack the factory transmission cooler. About $115, but you have to buy the Hayden 689 cooler and the Toyota ATF thermostat and lines.

https://www.tundras.com/threads/transmission-cooler-bracket-kit-hayden-679-689.153340/

The factory cooler worked fine, but it's not the easiest to retrofit since the AC condenser is replaced with the combo ATF Cooler/AC condenser.

Update:
Ordered bracket and AN fittings.
Will start to slowly work on this project.
Thanks for the heads up. I did not see this one before until you posted. Only knew about Setrab.

 

[D60]

Someone in one of the Tundra threads claims he lost 2mpg once he installed a cooler on a '19+

In typical internet fashion, this appears to be based on one long drive.

Keep in mind we're talking about something that gets, let's say, 18mpg, so as a percentage 2mpg is extremely significant.

I very much struggle to believe a ~381hp V8 is going to be so additionally taxed by pumping ATF that's slightly "thicker" as to lose ~12% mpg. I might believe 0.5%

But, I read it on the internet so it must be true.....

 

[4wd]

The range is pretty wide usually even on Linear Solenoid, Clutch Volume Learning/Adaptive units....Ford & GM 6/8/10 speeds, ZF 6HP & 8HP, Aisin 6 & 8 speeds etc.

150°F to 200°F is good target for most automatic transmissions.

Yeah, don’t like mine reaching above 200° - ordered a small Hayden RC …

 

[Snagglefoot]

My 6L90 has the radiator cooler plus a factory “ Mini radiator “ in front of the main radiator. It did towing duty up and down mountains with a 28 ft trailer but no towing anymore. It has 280,000 miles on it. The fluid only hit 200f a few times and that was while maneuvering it to park when it was over 90 F outside, with only the clutch style fan pulling air through the rads