The port that is available on the left side of the transmission for the aftermarket sensor is really a pressure port I don't know exactly where this is located in the oil circuit but it does not give you any accurate temperature indication until the transmission body gets hot. When I had my 04 in for the trans upgrade I visited the dealer to get something out of my truck as I buy a few trucks from the dealer I was able to disscuss the upgrade with the tech at his service bay,he had my transmission out on a cart when I got there and I ask about the slow reaction of the aftermarket gauge he replied that I had installed it in a pressure port that is a dead end it is about 4" from the main oil flow and the oil at the sensor never move so it takes a long time for any reaction to be seen at the gauge. I ask him to show me where it should be installed in the transmission he said that was the only port in the transmission.

I drained the oil a total of about 6 quarts and took the pan off welded a 1/4" pipe coupling in to the side of the pan about 1" from the bottom reinstalled and put oil back in. The gauge now reacts very quickly infact when I leave the city on the way home the tempeture will fall if there is a cold wind and you can see the tempeture rise when you get in stop and go traffic,highest I have seen it is about 150 F but have not been pulling any thing and weather has been cool.

 

Maybe we can put in an aftermarket sensor in the pan location (like hdway) or the pressure port, and modify the factory guage to read the signal.

What I would like is to be able to use the factory guage, but have a reliable, known reading.

 

Just returned from a 700 mile trip towing my 6000# travel trailer. Ambient air temp 80 to 90F. Isspro trans temp 170* most of the way up to 190* stop and go traffic on I-95 thru DC.(rush hour at 2pm on a thursday?) I was thinking about an aftermarket trans pan but don't think I need one.