If you don't have the tool you can use a hammer to smash the gear onto the shaft as well until the gear splits open like a peanut. This usually damages the shaft and the large gear and the crankcase and the seal if it was good before you started and sometimes leads to lacerations so wear goggles to protect your eyes from flying debri. This is not a recommended method but it does remove the gear and is highly effective during fits of rage but only mildly so when you aren't very mad. Sometimes getting drunk helps but it usually makes things worse, as with most vehicle related tasks. However, if you damage the engine you can blame it on the alcohol instead of your own stupidity, which can be comforting since being stupid isn't really useful or attractive, but being drunk is usually acceptable if you wait until after 11am.
Disclaimer: don't do this it's stupid, unless you're drunk.