[rheavn]

Try turning the override switch off. You may find that the previous owner did not close the slide properly and your level light may go out on the dash--sounds like many people once they have a problem just leave the switch in the override position and disregard the level light. If with the switch off the trans will not go in gear & level light stays lit, then the sensor is not telling the control box(the big box) that the slide is locked in place. Look over the top of the slide valance and I believe you can physically see if the locking pins are in place without dismantling anything. If the locking pins are not down in the pin holes, you could have a locking pin solenoid problem.