My father was riding my quad, and stated that it made a loud pop noise. After it made the noise the quad stopped going into gear. The gearing seems to be messed up. Neutral acts like first gear and once you shift into first gear the quad dies. I currently have the quad apart. There appears to be no damage to the gearing, the shifting forks, or any damage to the drum assembly. The gears seem to lock up when you spin them. I have no idea whats going on, any help would be appreciated.