Don't think you want my broken motor, its got the same issue as yours.
I fitted an uprated cog, and then the spindle sheared, I got my student Blacksmith Artist son to get his tutor to weld it back together. In the meantime the spindle from my 'spares' car was fitted, which also promptly sheared. The repaired spindle has now been working ok in the car for over a year.
A friendly local car repairer/ engineneet/ fabricator should be able to weld yours, probably cheaper than buying a whole motor.