My 1996 Seville seems like it has transmission solenoid problems as when in drive it seems to stay only in 2nd. However, I get no codes and no Service Engine light warning. I had this problem on my Concours and I did the work myself but I my SES light was on and the code came up. If not what else could cause the car to stay in one gear. At 40 mph my car is around 38 mph or so. Any info would be appreciated.

Anyone have any ideas? I checked all relays and fuses. Still no codes but it feels like it is in 2nd gear all of the time.