i was driving a BMW 635 CSi auto years ago with a load of drunk passengers past Tolworth on the A3. the rear passenger (who owned the car) managed to kick the selector into reverse at 80mph, at which point the box fluid boiled instantly and i had to coast off, park up and wait for everything to cool down! 20 min later it worked again - result. i also established, on a different day, at what speed a V12 XJS auto changes up from 2nd gear to 3rd on full throttle - 110mph. those were the days.