Wife and I tore the mixer apart expecting to find worn or broken gear of one variety or another. But we were surprised to find all the gears in good shape. We took the planetary out but it looked fine as well. Stumped we thought about it for awhile and realized that the planetary had to be bent in some way though it wasn't obvious.. The following worm gear no longer slid down easily on the shaft so we took a chance and ordered a new planetary. It arrived quickly! We installed it and along with ordering additional grease the Mixer was back up and running immediately!