CK25 engine problem

I have a CK25 with 800 hours on the engine. I changed the oil today, and when I removed the drain plug from the left side, 3 pieces of metal dropped out. Once I got them cleaned up I could see they were gear teeth that had broken off. The engine starts and runs perfectly. The teeth are very shiny, like they are chrome plated. Each one is about 1/2 inch long and 1/8 inch tall.

Can anyone point me to which gear these may be from so I have a place to start looking?

Also, can anyone point me to an engine repair manual?

Thank you,
Jason

CK25 engine problem