How can I remove the drum from a Belle cement mixer?

I have a Belle upright 140 series cement mixer, which I am attemping to remove the drum, without success so far. I have removed the rear oil housing to gain access to the ball bearing, which I have removed with a bearing press. The drum seems to be held on its shaft by a gear, which in inside the gear linkage housing. I would like to know how the gear is removed from the drum shaft. Any ideas will be gratefully appreciated.