Bosch selector knob broken

[halo]

Have a bosch 11236VS hammer drill. Took the unit apart and did a rebuild with the kit. Only problem is that the selector knob is now stuck in the drill only mode. I placed it back on without any problems and clicked the knob from the hammer drill to hammer then to drill mode. It now wont go back to the other modes and I can't remove the selector knob without breaking it. Any ideas as to what to do. I've been working on this thing for an hour and give up

Thanks

[Dale]

Try this link to a video. YouTube - Taking Apart the Bosch 11224VSR & 11228VSR Hammer Drills the tool is very similar. to the roto hammer you have.