Also get under your car and take a look at the shifter linkage rod... the one that goes between the bottom-most lever of the shifter up to the lever that attaches to the side of the transmission. Pay particular attention to the plastic bushings on each end of this linkage rod and the adjustment lock-nut at one end of the rod. This could be a case of a failed bushing that has completely fallen out!
Get back to us on the results of this inspection.
Regards,