I was running gas out of mower while it was in neutral, it jumped gears and started climbing a milk crate. I could backup off milk crate, so I run gas out of mower while holding clutch in until motor stopped. I think a spring broke, but have no idea what to do to mower. It is in first gear I believe. It made no noise when jumped gears and climbed crate. It had plenty of power. Need to know how to start motor in wrong gear.