Kitchenaid Artisan & 5QT Stand Mixer Worm Drive Gear WPW10112253 with 2 x Shims.
Part number WPW10112253. This Gear Fits Both Artisan Tilt Head and 5QT Bowl Lift Mixers. The Shims are a Genuine LKS Spare Part. Which is generally caused by mixing a 'heavy load'. but the motor is still running, then gear has broken.