Disassembled mixer, found stripped worm gear and ordered part after using Appliance Parts Pro schematics for the mixer. Ordered part and recommended new grease. (I received the next afternoon, incredible delivery service.) Cleaned old grease out to remove any metal particles and reassembled mixer. Very simple, uncomplicated repair. I purchased a snap-ring pliers set to make the job easier. That and a Phillips screwdriver were all the tools I needed.