I have a 2001 that I noticed was leaking what appears to be dark gray to almost black fluid from the R side of rear end at the tire. Forgive my ignorance but not sure if a GW has a rear differential but if so it would appear to be coming from there. Drove it home (10mi) and seems to run fine but too a while to get it to go into neutral, would switch gears easily but not find neutral. Two questions: First is this a leaking differential - I'm sure I need to take it to be seen about so Second: Is it safe to drive it to dealer or should I arrange a tow. Thanks.