1999 Saturn SL2 Intermittent hard shift

There is a service bulletin that states that due to normal powertrain vibration, there may be a broken or partially broken wire near the connector at the transmission. You should look for "distorted" wires near that connector. The wire could be broken inside the casing making intermitant contact. If the wiring is OK then the most like cause is buildups in the valve body that controls the shifting.