Missing Transmission cooler.

Elaborating on this further. Heating up while idling would need to be addressed separately. Engine rpm is low, so both the radiator fan and the transmission pump run at low speeds. A larger aux cooler might not even help. Electric fan conversion might. Put the truck in neutral with parking brake on if you idle for a long time, so the fluid doesn't heat up in the torque converter.

 

I don’t appear to have one either. 2020 DCLB V6. US built. New 2 weeks ago.

 

What’s the build date on your door jamb?

 

3/20

 

Where was yours built?

 

Texas

 

That's 3 people now without it? Between that and it being removed from the Tundra I think we know what happened here. Toyota is saving a few bucks.

 

Yap. Actually just installed a fan. One of these days I'll get around to installing the larger cooler I have sitting in the garage. For me it's a fair data point on the cooling ability of the system, even with restricted air flow which could easily happen low speed 4L wheelin.

 

I wonder if that would be a fluid weight issue more than a temp issue.

 

Nice. Do you know exactly how much fluid this added P man?

 

After a few hours of 4lo crawling in Texas last summer I experience some odd shifting, not really what I would call slip but something in the system def wasn't happy. I parked the truck for a couple of hours and rode with a friend. When I came back and got it and headed back out on the trail everything was back to normal. I suppose I should think about an upgraded cooler and a fan.

 

Nope. I did a drain & fill and then put it into temp check mode as per this thread. It's not hard, just mundane.

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

Then I made sure to get it to a temp where I needed the cooler to work (because it then opens additional cooling area in it) and topped it off again.

I will say it made a HUGE difference in towing 4k+truck loaded in the ADK mountains. Probably a 30-40° swing and I pretty much never hit 200° max

 

This is a perfect example of how things not acting right aren't just related to towing. The transmission fluid rests in a pan just like the engine oil. If you are driving on extreme angles, especially in extreme heat, things could go south real quick. Sadly, there's no way for you to check the fluid in the transmission easily and unlike engine oil, extreme heat will damage it quicker than engine oil.

 

Nice, I may consider adding one too. 30 - 40 degrees is huge when it comes to tranny fluid temps. So this additional cooler only opens up at a certain temp? How is the bypass plumbed in?

 

From the tru-cool site:.
"Automatic transmission fluid (ATF) is more viscous when it’s colder. Tru-Cool Low Pressure Drop (LPD) Transmission coolers have a unique cold weather passive bypass that allows the thicker ATF to flow more efficiently through the cooler at the top of the system."

Plus I pretty much took brand recommendation from @gearcruncher after a discussion with him.

I need to add the additive he suggests at my next self-flush....which I'm long due for.

 

Looks good! Nice and clean install

 

Thanks!

 

Yeah it's easy to get this trans hot imo

 

2/2020 Texas. I have the aux trans cooler.

 

Toyota took off the auxiliary, air cooled transmission coolers from almost all of their truck/suv models recently to save money.
They determined they were not necessary to prevent transmission damage within the warranty period... it's really that simple of a business decision, less material and labor cost means higher profit margin.

If you want one, just buy all the oem pieces from a model that did come with it from the factory, and add it to your vehicle.

I added one to our GX and the temps dropped 20-30 degrees across the board monitoring with obd2 and fusion app.

If towing in really hot weather, one could pin open the thermostat on the ATF warmer, near the pan, to start the cooling process sooner allowing the temperature to increase at a slower rate and reach a lower overall temperature.
If you can change your driving habits to keep the TC locked up, this will help keep temps down as well.. or there may be a TC lockup kit available to be added for pushbutton activation, this would help a lot when towing...
https://cruiserbrothers.com/brands/wholesale-automatic-transmissions/
also the OVtune has a TC lockup feature apparently...