Richard B Sun Prairie , WI November 21, 2025 Appliance: Whirlpool 4 1/2 Qt. Stand Mixer Classic - Tilt K45SSAC-0 Whirlpool Mixer K45ssac-0: Loud clicking noise. How to replace Center Shaft O Ring. I replaced the hub gear and the gear that it meshes with. I also replaced the prong on the center shaft and did a re grease. The mixer is now running smooth and quiet. Do-It-Yourself Rating: Repair Time Estimate: 15-30 minutes