These trucks have weak power steering pumps and no power steering fluid cooler. The fluid is probably shot. However, properly flushing is difficult and the industry has mixed feelings on wether a full flush should ever be performed, so a 'partial treatment' is generally the safest route with positive results. If the fluid is chocolate colored, no longer translucent, or smells burnt, perform the following proceedure. Use a turkey baster and remove a few ounces of fluid from the power steering reservoir. Put the old fluid in a milk jug or 1 liter (Pepsi) bottle temporarily. Replace it with new fluid or a fluid treatment (there is a 2-part fluid treatment made by various manufactures that reduces squeels, moaning and leaks.) Run the car a few minutes, turning the wheels left to right a few times to pump the new fluid through quicker. Turn off and repeat until you have used all of the treatment/fluid you purchased. Recycle the old fluid at the place you purchased the replacement fluid using the container the new ...