06 polaris 330 magnum wont move in any gear , whats the problem? where do I start troubleshooting?

I have a 300 mag 4x4, replaced carb,fuelpump ,spark plug and wire cap - when given throttle it dies what is left to replace?

Make sure the spring on the brake pedal that operated the park interlock hasn't stretched or come off the interlock, If the interlock and spring are ok,the problem most likely is behind the gear selector cover on the transmission. Water,moisture can get into this area and corrode the shift gears up or possible you could have broken tooth on one of the small gears