I had to shift between Rev. and Dr. about 10 times today to get turned around in a tight spot. When I was done and started to drive away the auto. would not start out in 1st,only second. It kept doing this until I turned the truck off and then it would start out in 1st but would not shift until 2400-2500. If I stopped and went into R. then D. it would not use first again. It is an 02 with 51000 miles and no trans. problems until now. Anybody got any ideas?