ok I know this was talked about and I did searching on this when I did my install. I was wondering if gm put on from factory where would they have put it? I have mine installed in the out line to the trans cooler I was just wondering...

All 4L80E transmissions have an internal temperature sensor; it's a small thermistor built into the trans wiring harness. It feeds the info directly to the PCM, so I don't think you could tie into it without causing problems.

Ic I forgot about that one.

That "sensor" is built into the wiring harness and it lays in the fluid in the pan. According to my FSM, it will set codes (on my '93 that is). One is high trans temp where temp is > 300 deg F, can't recall the other spec.
Once the fluid gets to that point, you have been in the danger area already and your fluid will cook and smell like bad meat. :eek: YUCK.
Don