Without a spinning auger, snow isn't ingested or thrown. As un-ingested snow piles up in front of your snow blower, you face more resistance and slow your clearing speed. When the shear bolt busts, the auger shaft continues to spin, but the auger itself isn't spinning. If it feels like your snow blower is pushing snow rather than processing it, or if you see snow building up outside either side of your auger housing, you likely broke a shear bolt. How to tell if your shear pins are broken