Had all fluids changed on car in anticipation of some long road trips last summer 2013 and car had over 90K; had transmission flush (but did it once already at around 45k with no problem. Not even sure if this was a problem, but one week later the transmission when car was hot after an hour of driving with NO issues just suddenly after slowing in traffic would not shift out of first gear, had to pull off road and shut car off, wait til cooled off (about 20mins ) and start car again and it was fine after. Has duplicated this 2 more times under the same circumstances and ONLY in hot (over 80degree weather a/c on or not) after 60mins of driving and after being stop and go traffic. Transmission specialist/dealer could not find problem but recommended a new transmission in order down the road??? My own research on net and word of mouth shows it may be a transmission speed sensor which I will be replacing this week in anticipation of a long road trip... will edit this entry upon my return as to whether it works..... although weather is still cold, has not done it all winter but I have not gone on more than 40min ride??