DIAGNOSIS Partly yes, and partly maybe. The Vitamix 5200 is famously loud—it's a 2+ peak horsepower motor spinning a heavy, blunt blade at very high speeds. A loud, powerful whine is normal. However, a grinding, rattling, or screaming noise is not.
FIX First, identify the noise. Run it empty on variable speed 10 for just a second. It should be a high-pitched, consistent motor whine. Now, put about 2 cups of water and a drop of soap in it, lid on securely. Run it on high. The sound will be louder and more of a roaring vortex sound, but still consistent. If that's what you hear, it's just the normal, powerful sound of the machine.
IF THAT DIDN'T WORK If you hear a metallic grinding or a loud, irregular rattling, there could be an issue with the blade assembly or the bearing in the container. Make sure the container is screwed on tightly to the base. If the noise persists, the refurbisher may have installed a faulty container. Contact them about a replacement container under warranty.
HEADS UP The noise is largely from the vortex of air and food inside the container, not just the motor. Taller, narrower containers (like the one on the 5200) are louder than the newer, shorter "Low-Profile" containers. Using a damp towel folded under the base can muffle some of the vibrational noise.