2004 9-5 gears slipping
 

Hope someone can help. I have a 2004 9-5 with 65000 miles on it. After driving on the highway for any period of time, and then back to city streets. It feels like the transmission slips on initial take off. It is an automatic trans, and seems to be at third gear. The car runs great other wise, and I don't know if I am causing more damage each time. I have asked two service workers and they suggested a transmission flush. I thought that it seemed early for this process. If this is a typical problem, someone please let me know. Thank You