I would think an out of balance driveshaft would show up more as a high speed vibration than violent shaking. But can't hurt to check it. Maybe the drive shaft is bent.
If it feels like it's coming from the left side of the vehicle, check the tires for possibly a lead weight from balancing the tire being thrown off, or maybe a knot on a tire has developed.
Last edited by Roy Rodgers; 05/28/2013 10:16 AM.