When driving as soon as I get to about 140* the gauge on dash pegs on hot and my scangauge 2 shows 8126*. No clue what is going on. Pull dipstick and fluid level is correct with no burnt or off smell. Yes the T/H was flashing. Ideas please

 

My answer depends on what vehicle we're talking about.

 

Sorry Mark. My 03 Excursion

 

It's most likely the trans fluid temp (TFT) sensor. It's located inside the pan. It's a common failure. It's really easy to change once the pan is off.

 

Thanks so much. Sure sounds better than a new trans.