When I joined up my knees just clicked, then I started to embark on the Grey Funnel line with associated ladders, they then began to clunk, then I started Mountaineering and they started clanking, my knees now go click, clunk, clank at my last medical I asked the Doc about them, he asked if they hurt, I said no, he said then that's normal! I think everyones knees click to some extent or other.