If your shifter has been damaged and has a loose or wobbly feel, there are a few things which could be the cause. The teeth on the inside of the spline can become rounded off, the spline can become elongated or the locking bolt could be stripped from over tightening.

The cause of the rounded teeth or elongated spline are typically because a gear shifter has been made out of a softer material than the actual gear box spline itself. They are made this way so that in the event of a crash your shifter will fail before the force of the crash is transferred into your gearbox potentially costing thousands of dollars where as a shifter is typically under $50.