drive pinion on a Ransomes Marquis

Hello,
The drive pinion on my Ransomes Marquis is broken and I want to replace it. However I don't succeed in taking off the broken one.
Can somebody help me?
Thank you,

Hey Keith
I do not know anything about your machine so I recommend to clean it up and inspect the collar of the gear to make sure there is no set screws, if nothing is there you will need a gear puller to get it off and not risk damage to anything else.