I just picked up a 2001 Ford Ranger 3.0 with a 5 spd manual trans. This truck came from out west, and has no rust. The fluids, however, are in need of changing. The power steering calls for ATF, but looks and smells like power steering fluid(although very black and nasty). Using a suction gun, I can only get a small amount out of the reservoir. Can I do a fill and suction several times with ATF, or are the two types of fluid incompatible, requiring a full flush and refill?