Ralph O Whittier , CA June 30, 2018 Appliance: KitchenAid 5-Speed Blender KSB5ER4 Kitchenaid Blender Ksb5er4: Drive gear worn out. How to replace Blender Drive Coupler. Fix was easy with the video provided. Thanks. Do-It-Yourself Rating: Repair Time Estimate: Less than 15 minutes