So I was running an Auto-Cross on Sunday and I made my last run of the day in the late afternoon. As I was driving at about 10-15 mph from the course to the parking area, the transmission seemed to be stuck in 3rd gear. Then I noticed the temperature gauge was about half way between normal and hot. I let it idle for a while and it cooled back down to normal after about 3 to 5 minutes. I've never had that happen before and I've been running Auto Cross events for over 10 years. Any thoughts?