Eddie, you should consider yourself lucky to get 600 hours out of your gearbox. I run a Rotax 912iS and during a routine oil change found a piece of metal on the magnetic plug. It was recommended that it be torn down for inspection, 368 hours. It cost $2250 in parts to rebuilt it. I bought a shop press and did the work myself, pretty straightforward. I was also very careful to keep the RPM’s no lower than 2000, always brought the RPM’s up to 2000 as soon as possible on roll out. I sent pictures and filled out a report for Rotax, no reply so far.

Frontier Fox