if not the steering belt that is screeching could be the power steering that has the problem.. Me, as an experienced driver regarding the screeching first cause could be not tight steering belt or need to be replace baka pud2x.. the steering belt should be tighten by an expert mechanic coz even though you feel it that it's so tight it still screeches.. 3rd possible cause could be the steering as I've said..

notice any leak or bleed ?