I have a 1993 Buick Lesabre that runs perfectly went to drive home and came to a stop light and was waiting for green light to go and than car would not move. Still runs but when you shift to any gear doesn't move but will stay parked when in park. Car is not leaking any transmission fluid and is full no smoking car not wet on the inside or nothing. Gears will move to reverse, drive, low drive but nothing happens.