This is a planetary gearbox. The housing is a simple revolution of the cross section provided. Then add the various holes. There is no indication of how many holes so you must use the TLAR method. (That Looks About Right)

The housing is in three parts. Notice how the cross section hatching changes directions at the joints of the three sections.

Unfortunately there is insufficient information on the cross section drawing provided to detail the housing. This is going to require a lot of guesswork.

Here’s an example of an aligned section view. It gives a good example of holes being directly opposite each other in a section view giving no indication that there is in fact an odd number of holes. If all you have is the section view without the parent then there would be no way to ascertain how many holes were in the part.