How do you change the power steering pump? Is it very difficult?

REMOVAL

1. Remove tires with power tool.
2. Remove side splash guard from vehicle with power tool.

3. Remove heat insulator from vehicle.
4. Loosen adjust screw and oil pump fixing bolt, then remove belt from oil pump pulley.
5. Drain power steering fluid from reservoir tank.
6. Remove piping of high pressure and low pressure (drain fluid from their pipings).
7. Remove mounting bolts, then remove power steering pump.

INSTALLATION
Install in the reverse order of removal.

After installation, adjust belt tension.

After installation, bleed air.

The noise should not be from the power steering pump. The most common cause for such problems would be the serpentine belt or it auto tensioner.

Have you checked the fluid level? Has it ever lost any?