the vibration thing is quite true, even in modern tanks (well,... at least in my cold war days).
In my days bouncing around in one of those cans we constantly had the driver checking hoses and other lines to make sure they were tightly secure. the rational was that if your tank is hit, a hell of a lot of energy is passed from the projectile into the hull (assuming a hull hit) and things get knocked loose.
It would make sense that a tank hit but not knocked out could potentially have an engine fire and the crew bails. The fire burns itself out for lack of fuel or air and the tank is later easily recovered. I would think such numbers would be rather low.
Words ought to be a little wild, for they are the assault of thoughts on the unthinking - John Maynard Keynes.