if it's JUST whining and you have no steering issues, you may need more fluid (check level) or you may need to replace the old fluid.

other than that, just suck all the fluid out, unhook lines, change pump and reverse with new fluid. and viola. just dont get a a-1 cardone remanufactured pump. i got one and i seen no change at all. got a used pump from morads for half the price and it was golden.