5r55 trans shifing into overdrive when turned off?

[JJ427R]

Was at Road America last weekend on track, late Saturday trans temp got to about 210*
trans started shifting into overdrive by itself, any trans experts have any ideas?

After it cooled down and 5 hours home it is shifting normally but guessing it's hurt?

 

[01yellerCobra]

I know some of the older transmissions will still shift into over drive to save themselves. Maybe it was shifting because the ECU felt it was too hot.

 

[406guy]

Road America huh? Love that place. What was your top speed at the end of the big straight that goes up that hill?

 

[JJ427R]

Road America huh? Love that place. What was your top speed at the end of the big straight that goes up that hill?

That straight about 120, car gets a little light in front coming over the hill and gets a little squirrely so I hold off a little, I'm faster on Moraine Sweep, about 130 there, had worn out tires this year so was struggling in the corners, a couple laps from Friday....