I finally got into checking it out.
to my suprize the primary gear was cracked as you described. the reason it cracked was the way it was manufactured.
a plastic gear formed around a metal hub will always do that. Plastic never cures completly. when it dose it shrinks. I found 3 vendors with the gear. Of the 2 the gear will need aditional machining. Nothing major. just the bore needs resizing and make the hub smaller to clear the other gear .The other just the hub needs to be turned dow to clear still trying to get a price..The gear is solid Aluminum. NO plastic. MY problem now is I need a centeral gearbox and the idler gears and the bushings. Someone tried to lower the motor removing the first idler gear. That's why Im missing the motor mount. That also explains why the gear box is all hacked up.
I also need all 8 dummy shocks. The lights for the roll bar and the hood stack. Lets work out a deal.