Power steering problems

The past few times i've started my XJ there has been a noise from the power steering "area". It's kind of loud at startup and then it's just when turning the wheel left or right there's a loud groaning noise. I checked the fluid and it seems to be full but when checked after a few turns back and forth it looks discolored and brownish. I just bought some PS fuid tonight and i plan on changing it out tomorrow afternoon. Is it possible that the noise is just from the fluid itself or is it most likely the pump? BTW - '88 XJ poineer. I don't know if the pump has ever been replaced. The engine was replaced about 4 years ago, but i'm assuming the pump is the original. THANKS

Start by flushing and replacing the fluid, but you may be due for a new pump.