60 D knocking?

[scuba e]

So a week before my next trip I pick up my old style Nikon 60mm lens. It has a new knock/rattle noise feel. It is not as if something is rattling around inside, more like it suddenly aged 20 years. It still gets focus. The aperture blades all function but it feels like there is more place in the telescoping parts.
I use this lens weekly and as of last wednesday it was fine.
Anyone have any ideas?