Just bought a '99 s80 for my son. It has 100K miles and looks great in and out. Ran great for one day with a small coolant leak...appears to be from the overflow. I left town on a trip, and that night his car would not engage from Park. The shift lever moves, but will not engage in any of the drive positions. It will move into those positions, but snaps to neutral when released. The only warning light showing is low coolant. Any ideas? Please help...