Volvo Repair: 240 Reverse Vibrato, flange bolts, output shaft

Question
I have a 1989 240 DL Sedan, automatic transmission.  When in reverse, the shifter stick vibrates (a rhytmic distinct knocking).  Is fine in all other gears.  This is a new problem.  What's going on?  Thanks...

Answer

Hello Nevin,
            Your problem may be related to:
          ***Transmission mount is worn or broken.
          You ran over something and it hurt your car.
          Trans. output flange hut loose.
           Output shaft bushing very worn.
           U-joints worn...u-joint flange bolts loose.
          ***Rubber mount for center support bearing on                            
           driveshaft failed....or bearing
           Motor mounts worn/broken.

        *** my likely choice

         Bilbo