My transmission hard shifts into second and thirsd intermittently when the transmission gets hot after driving in the city for awhile. This doesn't happen all of the time, but only occasionally. I read in a tech bulletin that this is sometimes the cause of a faulty sensor in the transmission coupled with the computer learning system of shift points (forgot the technical acronym). Does anybody have any ideas? Can the sensors be changed out while the tranny is the car, or do I need to pull the transmission and open it up?