I think it may be a common problem - mine looked like someone previously had gotten out their frustrations with a hammer. If you look into the "receiver" down alongside the stick, you should see a metal clip and a bit of rubber on each side. There is a barb in the center of the steel clip that engages a small recess in the stick. Use thin screwdrivers, slivers of sheet metal, a steel rule, whatever and slide it down next to the stick (both sides). You should feel when it passes and pushes back the barb. The stick will then pull out with practically no effort. I made a sketch at
http://chuckthetruck.homestead.com/files/shifter.jpg

http://www.chuckthetruck.com