Most times the automatic will slam into reverse after about 5 seconds of waiting and one of the forward gears either hesitates most anytime it shifts. Otherwise, once those obstacles have been passed the car runs fine. Once in a while it will hesitate going into a forward gear but always seems to make the next gear. The oil has been changed according to the book (3000) I took a transmission shop but they either really didn't know or the car was changing correctly when they tested the car several days later. Any ideas? The vehicle is a well kept 2003 my wife drives.