Sounds like air in the pump. With the steering centered, remove the cover from the resevoir and see if there are any bubbles. If so, your level might be a tad low and the pump is entraining air, whic can be very noisy and distressing.
2000 Dodge Grand Caravan SE
No matter what you fix, there will always be something else to fix..
"Warranty" is just another way of postponing the inevitable.