Hard to Steer

[Bajaoutlaw]

I tried a search of the forums first but the site did not work. My '04 2WD Expo now has a hard to steer syndrome. I would normally replace the PS pump but cannot believe at 55K it needs to be replaced. Very little groaning from the pump, not hard to steer the entire turn to turn, but enough the wife has a hard time. Tire Pressure is OK, not accidents and belt is good. No Leaks, just a sudden difficult time. Should I replce the pump or is there a valve in the lines that control pressure that can be bad?

Thanks