Alna, I have found this to be most common among the school bus/ taxi cab family. Front diff seals leak every now and than... also hapens on the rest of the colors too. My 03 looked like that at one point.
...off to the dealer you go. Since you have a nasty leak like that the internal stuff should be looked at just in case. You don't want your truck to end up like Adam's on Hells REvenge.
JK.
Also, since they will be opening up our diff., have your fluids all changed out. It's about time anyhow if you haven't had them done yet.
I would feel confident to do this to my own rig, but I don't put enough miles on them to warrant the service.
