Transmission fluid temp.... too cold?

Anyone know how cold is too cold when it comes to transmission fluid. Recent temps for me have been around 190 while the torque converter is locked and as high as 215 while accelerating or decelerating.

I pinned the transmission thermostat open and now I run 135-155 steady state with spikes up to 175 depending on the ambient temperature.

Is that too low?

 

Thanks, I was considering unpinning for the winter

 

After contemplating this for a while, I finally pinned the tranny thermostat open.
Speculation is that the thermostat doesn't open until 200+ degrees, I'm not comfortable with that.
With the way our transmission is configured, using engine coolant to warm/regulate the fluid temp, I am not concerned with running too low of a fluid temp.

 

My thermostat on a 2015 opens up at 240-242F. It closes at 225F.

 

I like to see mine get above 180 regularly to get rid of any water/condensation

 

Sorry if this has already been asked and answered but, how do you pin the transmission thermostat open/closed?

 

No worries. On the side of the transmission you will see a round metal "puck" tucked up on the side. Attached to it is a assembly were a smooth round metal dowel can be pushed into the assembly. You will see two holes on each side that a metal pin can be inserted to pin open the thermostat. Closed is no pin. Open is pinning it open. There is another thread that has pictures of the exact assembly.

 

No argument, just wondering how you determined this. Is this documented some where and if so, where ?

Implication is that Toyota thinks it’s ok to run 225F all day.


Greg

 

I have a Ultra Gauge currently and before that a Bluetooth OBDii reader since 2015 that read the TC temp and pan temp. Take a look at my pictures in previous threads. On hot days and unpinned usually towing it will always raise to 240F to 242F and a instant cooling down to 220F to 225F on the TC side and then steadily rise again under load to repeat the process over and over. Pinned it will not do that plus the temps are lower in the first place. The alarm will go off in the center display at 300F and goes off or turns off at @285F.

 

https://www.tundras.com/threads/install-complete-on-additional-transmission-cooler.12385/

 

I've been pinned open for a week. Tranny temp gauge still runs slightly below the middle. It previously always ran right in the middle.

I need a scangauge, but I'm really not concerned about being under temp.

 

Yes expect a @30F reduction. Plus under load you can shift lower and the ATF pump will push more fluid through at the higher rpm. I would recommend a Ultra gauge over a scangauge.

 

What model ultra and where did you get it?
Auto on and off with vehicle?