2008 Expedition EL, 29000 miles. My transmission slips when shifting from 2nd gear to 3rd gear. It only happens one time per day when I first drive it out of my driveway. Once in a while it shifts fine. I haven't taken it to the dealer yet because I will have to leave it overnight and then it probably won't do it for them. The last time I took it in they said there were no codes to indicate a problem. Does anyone know about this problem? Thanks.