Is there a problem if I find oil under the truck? I can't tell what oil it is, just that it is on the frame and top of the front axle. Looks as if it is coming from a metal drain tube about 1/2 to 5/8 inches hanging just above the differential in the front. It does not appear to be the drain from the fuel filter. I also have a slight fluid (oil or diesel) on the top near the injectors. The truck has 13K miles on it right now.