Q&A

I would suspect the power steering pump may still be the issue, get a second opinion before the warranty on the parts and labor expires. The viscosity of the fluid in the bulletin may be different. Perhaps try power steering additive by Lucas or Lubegaurd and see if that helps.

I suspect just a poor quality rebuild.

As patrick had said the viscosity of the fluid is thinner allowinit to flow through the system better. When Fluid gets cold it thickens and does not flow as well. This is the same for all fluids in a vehicle except for coolant. The fluid from the GM bulletin is very costly and you are to drain the whole power steering before adding it otherwise it will mix and not have the correct consistancy Which is why you would replace it in the first place. It is very true that the pump could be poorly rebuilt. The person that replaced the pump may had not gotten all the air out of the power steering system after the repair and this would cause a noise that you described. If you had the work done withing the past month the shop you took the car to may be willing to look at the car for no charge if they want to keep a customer.