If your 2000 Chevy truck has an automatic transmission, you can start it without the key by putting the transmission in neutral and then pushing down on the brake pedal while you turn the ignition switch to the start position. If your truck has a manual transmission, you'll need to put it in neutral and then push down on the clutch pedal while you turn the ignition switch to the start position. Either way, once the engine is running, you can put the transmission in gear and drive off.