D90 body lens mount
The 7 o' clock position? That's the AF drive. It's supposed to protrude since it mechanically couples to AF lenses. It's also normal for it to wiggle about.
Anyway, try checking for loose screws or bent leaf springs on the inner side of the mount. There should be three, one under each protruding tab of the mount.
|Hook Head Lighthouse by kroker|
from Best Photo of the Week
|Green turtle in the shallows by gcachon|