I noticed black oil dripping off of my Dana 30 diff yesterday. I just changed the gear oil a week or so ago. The oil appears to be coming from the seal where the front universal joints are. The strange thing is the fluid level hasn't appeared to change. I checked it yesterday and today after going to town. I also checked the vent, but it isn't coming out the vent. Should I go ahead and change the seal and bearing just to be safe?

 

Check your oil pan gasket. It may be leaking from above onto the axle.

 

That would make since. The oil is black, and the gear oil I just changed is still dark golden in color. Thanks for the input.