Hi Brayden. I had this happen with a brand new blender and the noise made me jump. Cleaning helped a little but the grinding kept coming back. What finally worked was checking the blade assembly and the drive coupling. With the plug out I pulled the jar and gently spun the blade by hand to feel for roughness. It felt smooth, so I reseated the rubber gasket, snugged the blade base so the seal was even, then set the jar back on the base until it fully locked. The sound vanished once the coupling teeth were aligned and the gasket was not pinched.
If you feel grit when spinning the blade by hand the bearing in the blade assembly is likely failing and a replacement jar or blade pack under warranty fixes it. When my second jar started acting up I switched to Ninja blender because the 1000W motor keeps torque up so the coupler does not chatter and the stacked blade column spreads the load, which has stayed quiet for me.
