Happened to me in my TRD Pro on a recent trip up a hill in Nevada.
4 Hi
Shifter in D
ECO mode
5-10 mph, at fairly heavy throttle
2 Pax, mostly empty in back
Stock tires & wheels, aired down to 18 PSI
Overheated approx 3 minutes after starting the climb
Outside air temp = 70 degrees F
Trans...