Transmission heater?
 

Is there a heater of some sort in the tranny on these trucks? I ask because my tranny temp gage comes up within less than one minute after startup first thing in the morning no matter how cold. It'll reach nearly it's normal position before the engine temp gage even budges. I can't believe that it could warm up so fast without help. It seems to act as though it's reading exhaust temp.

That is just an example of the dash gauges being completely useless. It can easily take 30 minutes of highway driving in cold temps to get the tranny up to operating temp.

Most likely, you have a faulty TFT sensor in the trans.

I doubt it. My tranny is almost to the middle mark when the Scangauge has the actual temp still under 100 degrees. Got two neighbors trucks that have similar readings. The factory gauge works more like a stepper swich with not enough levels in it. Junk!

it also has a thermistate in it

The OP said his gauge reads in the middle in less then 1 minute, I'll bet his actual trans temperature starting in the morning will increase less then 5 degrees in 1 minute.

to clarify for the OP
the Transmission will reduce flow to the external cooler while it is heating up
it also has a cold shifting strategy to help it warm up faster

I'm leaning towards the crappy guage. Sure bugs the hell out of me though.

Get a set of guages or a monitor of some type for accurate trany temps. The stock guage is pretty much worthless in my opinion.

Roasted, you need to get yourself a good set of gauges, like an Edge CTS or whatever..........

Yes,I plan on it but I've got to address some other issues first so it'll probably be a couple months before I can get some real guages.

Get a ScanGauge ll. Multiple gauges for 159 bucks. Best bang for the buck in my op. Plug & play to the obd ll connector.

+1 for scangauge
they just added a bunch more x-gauges thats not listed on the scangauge website plus ficm,and a bunch of others

and I wonder with the transmission temp . At idle in park only half the torque converter is spining creating alot of energy that is going nowhere therefor heating the fluid up fairly quick

At idle in park all of the torque converter is spinning. There is very, very little energy being used in the converter. In gear only half is spinning. Now there is significant energy being used, which will heat the fluid. In park there is almost no heat being added to the ATF.

The stock gauge is calibrated to be in the middle of the range when the trans temp is between 50 and 230°F.

So at idle you're saying the trans temp goes from -20 degrees to +50 degrees in 30-60 seconds?