My Kitchen Aid KSM150PS Artisan red mixer trembles

Kitchenaid mixer are supposed to make a slight grinding sound while operating under load. This is simply the gears meshing together while the motor is turning them, but if the sounds gets worse or is already a metal grind type sound this could indicate a broken worm gear inside the unit, and shouldn't be run any longer. However if your mixer isnt on SOLID ground this could cause the tremble as well.Hope this helps

Thanks