if it has the solid axle i dont think you can open it up, not unless you can somehow get that pressed fit nut off of the wheel without tearing it up, also i dont think you can get new gears,
was driving my my bandit the other day, weirdest thing happen! it has the solid axle in it but i hit the one back wheel against a ledge now only 1 wheel spins and the other just free wheels.....sux