Join Date: Jun 2000
Location: Kahuku Hawaii USA
if I remember correctly, there is a cable from the shifter to the trans. From the trans to the steering column there is a lock rod (back drive rod) that prevents the shifter from being moved out of park when the ignition is off.
From your description of the problem, it seems as if the cable has disconnected at either the trans or shifter end.
The fix may be as simple as bolting the end that came loose back on, or the cable may have broken.