Try pressing down on the brake pedal while shifting out of
Raise car safely,block wheels, unhook neg on battery. If your car
is equipped with a air bag ,it should be disabled by separating the
bright yellow air bag connector behind the dash plastic. On the
transmission there is one arm that is connected by a cable or rod.
Grasp this and move it and you will be able to move from gear to
gear as long as key is in the on position.Chances are the shifter
cable and or linkage is broken or became unhooked.While you are
under the car have a assistant move the selector while you watch
the action on the arm; it probably won't move but you can trace the
problem back to the selector this way. The problem may be in the
column itself. I hope this helps you.
Shift interlock may be a problem, some cars I have seen a wiring
problem from corroded wires in the console that shorted out the
shift interlock solenoid.
It may be way simpler however. Try applying the brake, pulling
the steering wheel to the lift or right a little and then try while
the tension of the wheel has been removed.