Your comparing a sensor that is buried inside the tranny to one that is typically installed in the pressure port... One is subject to air temp changes, heat of the metal around it and the flow of the fluid.
There is no issue with a tranny temp in the port, it reacts plenty fast enough.
Im completely friggin aware of the difference in how its reading temp. I installed the gauges. I put the temp sender into the test port on the drivers side of the trans pan. Im aware that the factory sensor that relays information is immersed completely in atf. Sorry for the elevated excitement but this has all been covered. Im reporting something.
The sensor that the cts is reading off of IS THE ONE THE PCM USES. There is no maybe there. I had a flashing od light last summer and my gauge was under 200 degrees... Apparently that little pencil eraser sized sensor for the analog gauge isnt transferring the temp quick enough. Its only taking fluid on its very end and under operating conditions who knows if there is ANY fluid to be had there. You cohld be getting the temperature of the case itself.
I think Jason might have inadvertently stumbled onto this. His fluid being more compromised than he thought it should have been given the temperature on his analog gauge.
Today a friend and I put the cts in his truck. The cts has a provision in its pid(what it displays) menu for an e99 trans. We selected that, just in case it matters. We ran his trans up to his operating temperature. By that I mean what he recalled to be where the trans is at temperature wise when the truck is warm. I asked him "what value is the gauge reading?" "170°". I told him "cts is reading 200°".
We drove the truck for an hour before the cts and his autometer ultra lite full sweep(for you guys that insist that they are more accurate than the short sweep) trans temp gauge. We ended our test with his autometer gauge reading 170°. It didnt go higher or lower once the truck was warm. Im thinking the case gets warm and determines what the gauge value is going to be. We went a step further and recorded a trans temp of 170 analog and 205 on the cts. We pulled his external filter,mounted before his trucool trans cooler ,and put about a pint of fluid in a jar and used an infrared thermometer to verify the temperature which was 207.
Gonna try it again on my truck but Im thinking the analog gauge isnt that accurate..:shrug: