Power steering pump OIL!?

I know there's fluid, but whoever had this truck before me had power steering OIL in the pump. The pump wouldn't engage on start. Had to give it a little gas to get the power steering OIL to flow. I flushed it out with transmission fluid and refilled but couldnt find the special oil he used so i just used power steering fluid. the pump works fine now. Anybody know where to find power steering oil?