Hi BigBenz, a very simple diagnosis - but just a bit harder to fix. More than likely, your problem is the selector rod that connects from the bottom of the lever to the side of the gearbox. To replace the bushes, you just about need to remove the rod from the car and carry out the replacement of the bush on the bench.
It could also be one of the bushes in the selector quadrant on your gearbox tunnel. Somewhat awkward to fix, but less likely to be the reason. Last but not least, it could be the parking pawl in the extension housing of the gearbox. More than unlikely, as it is a fairly solid lever that locks into the parking gear - no, you're not likely to break either of those components. Come to think of it, if the box is "clattering" when moving the car, the "park" position is not fully attained. So go back to the bushes, and the length adjustment of the selector rod. Regards Styria