2005 Dodge Sprinter van 2500. The power steering is failing, most of the time it isn't working. However at times it will work for a short while 1 or 2 minutes. The fluid level is good and the fluid is pinkish red in color. The belt is tight. The owners manual says to use ATF-D for powersteering but I cannot find it in any local stores, I was going to drain it and install fresh fluid. Any ideas what is wrong with steering?