Transmission fluid temperature

Does anyone have an idea what tranny temps should be on warm day, not towing with 2.7. Before cooler and after cooler(oem radiator cooler) trying to determine if mine normal

 

Below 200f

 

It can’t get lower than coolant temperature.

 

Typically it will be the same as the coolant temperature under normal driving conditions. Under load it will start to climb. Above 200 is bad. Above 220 is really bad.

 

@jpg366 Maybe transmission cooler with tow package changes things. Rolling down the highway mine is 195-185 per scangauge. Never correlated that to engine temp.

 

They can fluctuate quite a bit depending on load. So it is hard to say what "normal" is.

In general I would agree with what is posted above. At highway speed with no climbing at all, typical will be the same as coolant temps in the same scenario. But can change quite a bit as a load is applied. Climbing a hill or going over a pass, 200-210° could be normal.

Not always. It depends on how long those higher temps are maintained.

This chart was posted recently in the daily thread that shows the trans fluid life expectancy at higher temps.



https://www.tacomaworld.com/threads...t-gen-edition.138573/page-11103#post-30092550

 

Maybe what I meant to say is the ideal temperature is under 200. Once you go above that the fluid will start to degrade faster. If it's only for a minute, it won't do much. If you expect to get 100k miles out of your fluid, then you need to keep it under 200. Even after I added a transmission cooler, I will still get temperatures above 200 in Texas summer in stop and go traffic. This just means I need to change my fluid more frequently than 100k miles.

 

The temperature measurement is dependant on where you measure it at. The highest temp will be at the output from the transmission, this is right off the torque convertor. What you are measuring in the pan is an aggregate measurement and if there is any damage to the fluid due to excessive temps, it has happened way before you can measure it.

In modern transmissions this heated fluid is dumped back into the pan until the trans warms up, then the trans Tstat opens and send the fluid to the cooler, unless you own a Nissan, then it pumps it into the radiator coolant and visa versa, if you own a Nissan and have had a milksake tranny you know what I mean.

 

Great info from all you guys. I am in process of installing

$49 Hayden 678 Universal Rapid-Cool 9.5” x 11” Add-On Transmission Cooler – Not for Direct Replacement of the OE Cooler

Hayden 678 cooler and since my 2000 Tacoma doesn’t have sensor , my scan gauge 2 won’t help. I gotta add some kinda aftermarket gauge and I’d like to install sensor in tranny pan.(remove drain plug and replace with sensor) . Anyone got suggestions on aftermarket tranny oil gauge)

 

I will suggest these... https://www.pegasusautoracing.com/p...yBQ_Z2yuDrf56HwGC3RLAHzFWyTEjQ_M_TdhO8id3zqgY


A guage is just one more thing to monitor and break. You are concerned with max fluid temp. I am thinking that you put one on the pan on the drivers side and driver her around and see what the max temp is reached.

 

My 03' V6 auto uses the radiator to cool the transmission fluid as well.

I added a separate transmission cooler so the transmission fluid goes >transmission>radiator>added cooler>transmission.
I find my trans temps to be significantly cooler than before and when they do get hot they drop drastically as soon as the load is reduced like going from uphill to flat/downhill.