Hi,
I know this is an older forum, but the question is still quite actual
Just got a used K50 camera from ebay (my first Pentax).
A cluching sound when wagging the camera - for me too, it doesn't matter if camera is on or off.
After some playing around - I finally found what it was, and this was NOT the image stabilization system. It was the battery!
Battery D-LI109 - at least in my unit - has ca. 0.5mm free room for movement to the sides, while lock switch looks ok. After opening the battery cover and holding the battery still, the clutching sound disappeared - once again, image stabilization system has no sound on my camera.
So question to you guys - can you check if it's the same for you?