Torque Flight Shift Problem

Hi - Any help or comments would be appreciated.

Was out on a drive today (71 Duster w/ 360) and the floor shifter all of a sudden would not put the car in anything but the first low gear. The shifter moves to all positions but car remains in first only ... no park, reverse, neutral or 2nd-3rd.

The floor shift linkage seems to be okay ... have not been under the car yet.

Thanks