Back to your noise issue...
Without looking at your mount, it sounds like your mount is adjusted with a really tight worm/ring gear mesh. The PMC8 uses stepper motors so they'll power through and stop when they can't rather than burning out the electronics like the server motors on other mounts I've owned.
That being said, if you want to adjust some of that noise out, here's a good video that explains how to do that. The presenter is using a Celestron CG4 mount, but the design is the same as are the concepts of adjustment. Make the adjustments without a scope or counterweights on the mount. Also, do so with very small turns of the push/pull bolts involved (that will make sense when you watch the video). You'll find that it's a fine balance between a quiet mount with some backlash and a noisy mount with almost no backlash. I prefer something in the middle and adjust my mounts to that preference.
Of course, you can always send it back for adjustment. However, adjusting your mount is a good skill to have regardless of what mount you own.