I have found that many say a transmission temperature determines it's life. Now I know this is true and I feel I should do everything to keep its temperature under the magical 185 or so everyone seems to agree on, I wonder where to measure?

If I measure temperature after hard driving I find the pan surface temperature, measured with an infrared thermometer, to be say 194. I find the line temperatures goin to my radiator dependant on the radiator water temperatur (a little), around the 194 too.

When I measure through the filler tube into the fluid itself I measure 230.

Seemingly, just there where the filler tube is, I find the highest temp. Maybe If I continue my quest I will find even higher places.

Now I wonder. Everyone seems to use the two cooler tubes to go to large tranmssion coolers (22000 GVW). Now although that is what I would like to do, I always like to know how neceassry something is. If my tube temp doesn't go beyond 194 I don't have a real problem right?

 

i'd say to be more accurate you'd need to install an inline gauge

 

I had this same question not to long ago when I installed my 700r4. I installed an in-line temp manifold(fancy name for a t-fitting) from Autometer on the sender line to the cooler. I think though the next time I take the pan off I'll install the temp sensor in the pan.

About tranny life, I read that for every 20 degree you drop the temp, you double the life expectancy of your tranny.