Question on my new 2004 Boxster

[SHLATL]

I just bought a 2004 Boxster from my neighbor after having driven a number of Porches under the Porsche Passport program in Atlanta.

While underneath by 2.7L Boxster I noticed a slightly rusty gear exposed behind the engine that turns when the engine is running. Is this a normal thing? Here's a picture of it:


Thanks,

Steve