It's on the driver's side of the tranny...

 

BTW, for some reason I seem to remember someone claiming that they checked their trans temp gauge, with the sender in the test port, against trans temp readings on HPTuners or something like that, and it was very close if not right on. It's a vague memory though so don't take it as the gospel...

 

well my problem now is i have a 150 $ aem digital tranny temp gauge and a two guage autometer pilliar thats missing a gauge that was 75 $... i listened to someone that supposedly had some experience with these trannys and he told me they werent close that the factory would act weird and read lower than it actually was sometimes... so idk i guess if i get it in there il find out.. FML!

 

I would think that you would want to know the highest temperature that the oil reaches, not the overall average temperature, even if the higher temp doesn't agree with what the truck's computer thinks it is. I know that the oil temp in an engine is used to estimate the oil temp at the bearings, and it would be best to have the sensor in the bearing.

 

Just sell the trans guage and get an Aeroforce scan gauge to fill the other hole..

 

I discussed this with frank at performabuilt a couple a years ago and he recommended the pan over the service port. He said the temps at the service port would read higher....he didnt explain why but said the pan was most accurate.

 

I agree, if the trans fluid temp is higher at the test port than in the pan, then it is also higher elsewhere within the transmission...I want to know how hot that fluid is at it's highest point.