Hello Roman and Ira,
this C-drive has been running without oil for a while!!!
You can get access to the inside of the lower unit if you take down the front plate (where you see the big pin that enters the GRP keelstub), bolted with ALLEN screws.
You will probably need to get in touch with AMEL in order to buy the gears and bearings, together with the prop shaft bushing and seals.
If you are in an area with good machine shops, they will probably be able to make these gears (although they are complicate as helicoïdal bevel gears).
Thank you for these pictures. This is a very good example of what not to do (neglect the service of the AMEL C-drive).