I drive a 2001 dodge dakota slt 5.9L V8.one day my dad was driving it on the highway and it was icy, so he turned 4wd High on and after a while it started smelling like propane/natural gas. It has been months and the smell is still there when it gets warmed up and im driving it does anyone know what this is and how I can get it fixed.

 

Probably a fluid leak of some sort onto something hot.