First time on this forum; I own a 2000 Lexus 300es. Have owned it for 4years 100,000 miles on the vehicle. On the last 5 hour trip noticed transmission not going into highway gear. car was runnning at 4000rpm at 65mph. stopped for gas. started car, put in reverse then headed out onto highway-gears changed normally operating at 2600rpm. got stuck in traffic. As I sped up car did not change gears went back to 4000rpm. Did the turn off/ then reverse process and again and car went back to normal- lower rpms. This normal rpm transition won't happen unless I turn off the car and go to reverse. I tried other shifting methods. NO sensors issues.