I'm constructing a vehicle and got stuck on the housing rack.

It currently looks like this:

Visible are my top layer intersecting the housing at mid level and two layers below that, at 3/4 down and completely down.

The base for my pinion is done. Now I want to erect a house for the pinion around it (the black circle indicates it's position), without it intersecting my housing rack.

I'm pretty sure it wasn't hard to use an extruded boss in such a manner, but I can't remember how to do it.