WHat part fits in here?

HI, Fast Bob said i must rather try in this forum about my question. I have a BMW X3 2005 3.0 I A/T ,inspecting the car below , i saw this gap in the engin part, it seems that some part is missing,like a dustcover ?Can someone pse tell me the part name so i can order it form BMW.In the pictures you will see i covered it with a grey duck tape preventing small stones to get in there.

That's the transmission bell housing - it's supposed to be open to ventilate the torque converter.

HI CHAGRIN ,Thanks a million for your advise, i really appreciate it, i guess i better rip that duck tape off quickly ! Luckily i havent driven far with the ducktape that i have covererd the hole with.Thanks again