I thought that was a metal gear on my 730, and not the one that's most often cracked on the machines I have had my hands on. I have double and tripple checked this on my 730 because it has been such an issue regarding info on this machine. The plastic gears on my machine have turned to white after a period of cleaning and oiling. I know Bernina had slightly different varians on their 730, some has a plastic gear more than others. I wonder if there is a metal replacement part for the cracked gear on your machine? Except for the industrial models, I think the 740 and 840 was the most expensive of them all.