Our ex-firefighting truck had a waterpump via a power take-off (PTO): when the engine is running, you engage the PTO so it revolves and you can attach all sorts of machinery to it. This works even when the truck itself is in the neutral gear.
We don’t need a PTO for the camper and the extra piece with the round flange will be removed as well. We’re keeping the actual PTO-drive, but we need a cover for it. Mercedes probable sells those, but it was a small effort to design it ourselves and have it laser-cut in steel.
Cause the inner piece portrudes a bit, there’s an extra ring. A bit of welding puts the cover and the ring together. After painting, Iris can attach it to the gear box. All done!
1. PTO to gearbox 
2. PTO removed 
3. Naked PTO in gearbox 
4. Designed and laser-cut 
5. A bit of welding 
6. Iris attaches the cover
