Kept looking at Tubs’ original photo of the pinion and gear assembly. The assembly in his photo looked more recessed than mine. So, I pressed a wooden dowel against the assembly, hammered on it and the assembly settled in an extra 1/4”. Now the pinion and assembly both fit BUT the gears jam, the original problem.
Oh well, I have spare parts and they work, but I am still puzzled about what is causing the pinion and gear assembly to jam???
Thanks, everyone, for your suggestions. I appreciated them.