Blades and roller won't turn?

Went over stone and jammed the blade which in turn broke the white drive gear, replaced gear but the blades and roller still won't turn, I then took the top cover off only to find two shafts one to the engine which I think would be the clutch with a rubber coupling which I think should connect to the other shaft but does not there is a gap between them. I think this is the problem. Any ideas as to how I might close that gap. The mower is a Qualcast 35s year about 2003