question about kitchenaid mixers
My family has a 250watt k45ss kitchenaid mixer that my family uses to mix up stuff to bake. My mom with in the past 2 or 3 months has started using it to grind wheat, and she is concerned that she is wearing the thing out. She wants to know if the thing needs oil since it is making a grinding like noise at low speed, and an unfamiliar hum a high speed.
so is there anything to be concerned about? (note: the mixer is about 20 years old)