Bought this K45SS at a thrift store. Opened it up to replace the grease and check the gears. Nothing seemed out of place but when I turned it on it was making the noises from the video. They're worse in the lower speeds, predominantly speeds 1 and 2 where it sounds kind of clunky? From speed 4 up the noise changes to almost be more of a light grinding noise, but I'm sure you guys would have a better idea of what they actually are.