Not knowing how handy you are I would try to take the top of the mixer apart and see what is going on. It sounds like one of your gears is either slipping or has some broken teeth. If you don't want to tackle it a small appliance repair shop should be able to fix it for you.I just found this Maintenance ServiceYour Sunbeam Caf? Series® Planetary Mixmaster® Power Drive should be regularly checked. After approximately four years of domestic use, the grease in the gear compartment should be examined. We suggest at that time you send the mixer to your nearest Sunbeam Appliance Service Centre to ensure efficient, correct servicing. Just there recommendation but i guess a known problem.