Thanks a lot, @spikeyxxx , for this detailed review and the encouragement 😀! For me, it’s learning by doing since I haven’t modeled such a complex piece with many intersecting parts before. And your approach of connecting things first and then caring about the topology makes! Sometimes, I’m overcomplicating things, in this case certainly also as a consequence of insufficient experience. One challenge among many for me is to find a clever way to handle the holding edges that are flowing from one part into the next. I avoid 6-poles and keep 5-poles away from edges with the help of the holding edges. Exceptions from the last rule are corners where 5-poles not only can’t be avoided but are even necessary for smooth transitions.
Furthermore, I try to keep newly created mesh as local as possible instead of loop cuts running completely around the mesh. I also taking care, that the mesh is as evenly dense as possible (which is of course not 100 % achievable), since in some parts edges are coming very close causing unintentional bulges under the influence of the “Subsurf Modifier”. I know that I can smoothen this with shrinkwrapping but I don’t want to run into a bad subsurf modeling habit by relying too much on the “Shrinkwrap Modifier” which should only come into use if nothing else helps. The big question is only: When is thy point reached? I hope to finish the gearbox until tomorrow. Wish me luck! And once again thank you so much for your help😀!