This was from another thread a year ago. Looks pretty similar.

Transmission temperature monitoring with OBD2

"All right guys. Been using it for a while now, got it from 4Runner Club Kazakhstan. You need a bluetooth ELM327 adapter (Ebay) and Torque application installed on your Android-based phone. In Torque, you should create the following two custom PIDs:

PID: 21d9
Long name: Transmission fluid temp 1
Short name: TFT1
Unit type: *C
Max/Min: 220.0/-40.0
Equation: (((E*256)+F)/256)-40

PID: 21d9
Long name: Transmission fluid temp 2
Short name: TFT2
Unit type: *C
Max/Min: 220.0/-40.0
Equation: (((G*256)+H)/256)-40

These work fine on my 2006 T4R V6, and should work with any 750 transmission (V6 2005 to 2013, V8 2003 to 2009). I don't know if it will work with 340 transmission which they installed on 2003 and 2004 v6, but there's a chance it will - someone has to test it.

There are two temp sensors, one in the transmission, another one next to the radiator, the latter's readings are higher - it shows temperature of a liquid yet to be cooled down in the radiator.

I checked accuracy of these PIDs in Torque using another diagnostic tool (MVCI cable) and Toyota Technstream software - it showed diffrenece between Torque and TIS Techstream of around 1 degree Celcius - which I think was due to time it took me to switch between the two tools.

Now, the idea itself and PIDs were originally borrowed from one of Tacoma forums (Tacomaworld I guess), but when we checked their PIDs we found out they showed temperature about 20 degrees higher than the real one. That;s why we had to ask some programmers and Toyota fans from Russia to help us and now we all can use their correct PIDs shown above.

I hope it'll save you some time and money.

P.S. Just don't forget it's all in Celcius.

((((E*256)+F)/256)-40)*1.8+32
((((G*256)+H)/256)-40)*1.8+32
Those will give you outputs in deg F. "