Driving my 2003 today seen the "check gages" light on and the trans temp gage pegged on hot. CRAP, tranny time! look at the edge evo and it reads trans temp as -60F ???. Plugged in the torque pro and it reads 8,240F. At that point I figure its PROBABLY not that hot. Let it sit for a while and back to normal. Watch trans temp on torque pro as I drive it and everything is fine till it gets to about 150, then it jumps to 60F, then 30F, the 8240F. The cooler lines and trans pan are both feel normal. Picked up a new temp sender on my way home.

 

With that kind of a temperature swing you either drove from Mars to the sun yesterday or, you have a faulty sensor.
I think you're on the right track. Post your results.

 

Replaced the temp sender yesterday. All good now. I just changed the fluid not long ago so I didn't want to replace it. I got a clean one gallon container and drained a gallon out using the drian plug. The trans area was still clean from the last service so I didn't worry about dirt getting in the pan. I dropped the pan down onto a block and kept it under the trans. The sender is just to the passenger side of the filter port. Lift the small tab and turned a 1/4 turn and pulled it out. Some oil drained out from pulling the sender, but the pan cough it. Put the pan back on and refilled with the gallon I drained. I might have lost a 1/4 pint total

 

Excellent news. Even though you just changed the fluid, it is justifiable to replace it again because when you change it you never get it all out.
That said, either way you should be fine.

 

One of our 07s lost the trans temp sensor. Random deal, it was perfectly fine, shut it down for lunch, and an hour later immediately after restart is was going ape-**** crazy on the temp gauge. Glad it was an easy fix

 

I used the SP fluid and I have to special order it around here. I an very comfortable with the condition of the fluid. I think it must have been changed not long beore I bought it.