If anyone is going this route and pulling your own gearbox to send it in to a factory approved center for the 600 hour maintenance, there are a few gotchas you need to be aware of. First are the somewhat expensive tools required and their leadtime. The 877660 Rotax gearbox puller is over $500 and is on at least a 30 day backorder now. Thankfully Aircraft Spruce has one for about $100 that is an automotive slide hammer with a Rotax adapter bracket. If you are going to pull the drive gear off and include that in your maintenance, you need the 877445 41mm socket ($300), an 845430 lockwasther, and lotcktite 648 to put it back on. Note that Aircraft Spruce also has a cheap alternative to the 41mm socket.