GRDIII - Grinding noises?

I got a "like new" GRDIII from eBay, and it really does look flawless, as if it's never been used. It's my first Ricoh and I'm in love with it, seriously wonderful camera (You can see my work with it here: http://flic.kr/s/aHsjCvfVH3 ).

There are some strange problems though. It makes a truly horrible grinding noise when powering on or off, something I've never heard from any digital or analog camera I've ever owned. You can see an example in this video: http://www.youtube.com/watch?v=8ytroM3LW8Y

When moving from dark to bright areas it seems to take a long while for the aperture to catch up, and it makes a ton of chatter as it does so. Pressing the shutter halfway while it's in this process locks the exposure in whatever position it's in rather than actually setting autoexposure.

Are these normal issues with the GRDIII or do I have a defective sample? If these are normal in the III do they exist in the IV?