1998 audi a6 c5 something wrong i guess :(

[qoro]

It shouldn't be closed? It not a transmission ? Today I have removed the catalyst and have found out this I think that it shouldn't look so, is not it part of the transmission gear ? lol idk it must be closed or something... no ? :1zhelp:
watch the video and please add some photos of audi a6 c5 from bottom side to compare mine and your added photo ... ty
http://youtu.be/oFZpoxPGtgs

[NickPicks]

It looks like the starter motor ring gear on the flywheel. i'm not sure about the A6, but most cars I've seen have a cover over it.