Diagnosis
The brushroll end caps are worn out. This creates metal-on-plastic friction between the brushroll shaft and the bearing housing.
How to Fix It
1. Turn off and unplug the vacuum. Flip it over.
2. Remove the soleplate by pressing the two release tabs near the front wheels.
3. Pull out the brushroll. Inspect the black plastic end caps on each side of the roll.
4. If they are grooved, cracked, or significantly worn, they need replacement.
5. Order and install new Shark AZ3002 brushroll end cap replacements.
If That Didn't Work
The noise may be from a failing motor bearing in the brushroll drive assembly. This requires replacing the entire brushroll motor module.
Heads Up
Running the vacuum with severely worn end caps can damage the brushroll chamber housing, leading to a more expensive repair.