Focus transmission engaging only intermittently

Is it possible that a mouse chewing on the wires
inside my shifter column? The shifter changes
position smoothly but will go into gear and drive a
half mile or so, then it slips completely and the only
way I can get moving is to pull over and shut it off.
I was able to pull the trim away a little and under
the shifter was evidence that a mouse had made
residence and some wires had been chewed.