accidentally rotated focusing ring...damage??

this is a sigma 17-70mm f2.8-4.5 macro lens, i was examining it today and accidentally rotated the focusing ring in AF mode, i heard the gears move..im assuming its connected to the motor in af mode...anyways i dont know if i damaged it or not, and i dont have a body to test it on. after changing from MF to AF, the ring would make a clicking sound when i try to turn it( of course it doesnt actually turn).

has anyone done the same to their lens or know if i have damaged it?

thanks!

I've done that to my Tamron 28-75 more than once without any damage or concern. I wouldn't make it a habit but I would guess your lens is fine.

Lenses are amde to have some level of durability. Once of twice in the lifetime of a lens should not pose any sort of problem.

If that caused damage I imagine we would have a lot of threads about it.

You'd have to do it quite forcibly to break anything. If you hear the gears moving it's okay (but don't do it!). It's when you hear them break that you have a problem.