Originally Posted by
dehg5776
Dot forget that parts are interchangeable as well, so the PGB may have been swapped in from a different aircraft.
True in a way, but in fact the PGB is married to the core engine in the shop, and the full powerplant is then hung in the aircraft.
And strange as it might seem, the PGB supports the core engine in space within the nacelle; consider that the major mount loads are imposed by the prop torque, which are directly reacted by the PGB connected to the nacelle. I believe this is true of many other turboprop installations as well.