I bet it's the bushings. My 240D did this when I bought it. If you don't feel an audible "Click" when you push the shifter all the way up to park, it's the bushings. If it just hits the top of the shifter and goes to the left for park and you don't feel a click, you're not all the way into park.
It's not a hard job at all, I didn't even use the real nylon bushings (I didn't know about peach parts then
) I just went to the hardware store and got some good old rubber grommets.