1999 Jeep TJ Rear end

what size axles come stock on a 1999 jeep TJ 4x4 4cyl? Dana 30's or Dana 35's or both?

OK it depends on what axle front or rear. Front is probably a dana 30. The rear could be a 35 or a 44 depends on what they put in. So what I would do is call the local Chrysler dealer and have the last 9 of you vin number handy and ask them what it is equiped with. As for the grease all over this is probably a seal depend on where the oil is could be a pinion seal.