What is the upper limit of transmission fluid temperature?

The 2 compression fittings with the T fitting cost me about $50, they are all stainless. I got them from granger, they were the only place in town that could get me the 10mm compression fittings. The gauge with sender can be found at oriely's for about $60 otd. The gauge pod was about $75 shipped

To install the sender takes less then an hour, then run power, groung and signal to the gauge.

I also run a water temp gauge (3337), and its the same setup, except u need 5/8" barbed fittings into the heater hose, sine it already has a union from the factory so there was no cutting for that one.

 

When I had my '06 Prerunner I bought a ScanGauge specifically to monitor my transmission temperature, just because I couldn't check fluid condition on the dip stick. I towed a 3700 lb. Travel trailer and the Prerunner saw 225 degrees or so lots when climbing or during stop and go. Regular running trans temp was 180 to 190 for me.

I got a great deal on a new Tundra and kinda sadly traded in the Prerunner. I moved the S/G to the Tundra and get just about the same trans temp readings under the same conditions. The Tundra has a trans temp gauge in the dash. At 225 degrees on the S/G the pointer on the dash gauge doesn't move at all above mid range. Some guys on the Tundra bulletin boards say that it won't even start to go up until 250 to 260 degrees. I don't know how dependable their advice is. It's also stated that Yota WS trans fluid is a synthetic or semi-synthetic fluid and is designed to run at higher temperatures.

I've also read that the S/G temperature pickup for the Tundra is before the fluid goes through the cooler--the reason that the tremperature varies so quickly. Many trucks that always get low temp readings have their temperature pickup after the fluid exits the cooler. This is all info I've just read, so take if for what it's worth.

 

anyone ever find a factory temp threshold?
Looking to do some towing and would like to know ahead of time

 

I did not find this, but I did find it extremely helpful to explain how each temp will effect the life of the transmission fluid. The fluid is the life of the transmission, if it goes bad you are SOL.

 

Here is the official response from Toyota on the Trans Temp Light.





SubjectTrans Hi Temp Light Discussion Thread Response Via Email (Kym Strong)05/29/2013 08:45 AMDear Terry Tubb,

Thank you for your follow-up email.

We apologize that the Owner's Manual does not include the temperature in which the automatic transmission oil light will illuminate in your 2013 Tacoma.

If you are towing with your vehicle, the automatic transmission oil temperature light may illuminate at 302 degrees. If the light comes on, it indicates that the auto transmission fluid temperature is too high. If the light flashes, it indicates a malfunction in the auto transmission system.

For further evaluation, information and assistance, we recommend you contact your local Toyota dealership.

Regards,

Kym Strong
Toyota Customer Experience

 

not ALL trd off-roads come with external cooler. How do I know? cuz I have one without

 

In the process of setting up a new motorcycle trailer. Attached is a pic of the truck and trailer.

Trying to determine the effects/impacts of the trailer on the truck temperatures. Initial observations are…

Without trailer at speeds of 45-60 mph – coolant temp runs 189-193– trans temp runs 130-175.

With empty trailer at speeds of 45-60 mph – coolant temp runs 189-193 – trans temp runs 165-215.

No runs with a load yet, nor any runs in the mountains yet.

Some thoughts:

According to the scan gauge II, trans temps fluctuate significantly compared to coolant temps.

Trans temps can rise rapidly and dramatically (40 degrees in 10 seconds).

Hills (both up & down) raise the trans temp significantly.

At 215ish max temp, do not need an oil cooler (so far).

 

If you have the tow package, you have the cooler plus larger alternator.

 

I pull a lot with my 4000# trailer and sometimes with my dirt bike in the truck bed. I have climbed a lot of big hills and in high temps. The trans temp has never gone higher than 225 even climbing an 7-8% grade for 10 miles. It will stay hot until I stop climbing then it cools very quickly back to 165-185. The engine temp has never gone above 198. The trans temp sensor on the taco is on the output from the trans to the cooling system. When the torque converter kicks in during a 4th or 5th kick down the trans will heat up real fast then cool right back down. I consider this all normal. I towed over 5000 miles this summer without a problem.

The Taco manual says to change the trans fluid every 100K mile or if you are towing to do it at 50k. I change mine every 30K miles and it is discolored but still has some red tint to it. Another part that a lot of people forget about is the rear-end. That fluid can break down as well in the LSD rear. The manual says if you are towing to change that every 15K, I stick to this on the mileage. I did use the Lucus full syn fluid in the rear and it started to chatter in about 8K miles so I went back to the regular diff fluid and have had no problems.

If you service the truck correctly for towing it will serve you well. Remember that towing is hard on any vehicle and things will break even if you do everything right.

 

You also have an engine oil cooler , the fan clutch has a different temp rating as well as different pitch to the blades.