You are likely to get an oil 'mist' from a vent or breather tube -this is quite normal. The 'mist' cools around the breather and forms a small oily patch. on the axle casing.
Are you certain that the oil is coming from the vent tube and isn't due to a split in the metal casing or from the gasket/seal?
How much oil are you losing? The only other way you would lose oil is if excess pressure was building up inside the differential and to be honest, it's difficult to see how this would occur unless it has recently been over-filled with oil.
If there are drips of oil appearing on the ground underneath the axle/differential chances are that it's the cover seal or the pinion seal at fault. The pinion seal is where the driveshaft/propshaft attaches to the differential. The cover seal is the gasket between the metal cover where the filler plug is and the differential casing itself.
Answers & Comments
You are likely to get an oil 'mist' from a vent or breather tube -this is quite normal. The 'mist' cools around the breather and forms a small oily patch. on the axle casing.
Are you certain that the oil is coming from the vent tube and isn't due to a split in the metal casing or from the gasket/seal?
How much oil are you losing? The only other way you would lose oil is if excess pressure was building up inside the differential and to be honest, it's difficult to see how this would occur unless it has recently been over-filled with oil.
If there are drips of oil appearing on the ground underneath the axle/differential chances are that it's the cover seal or the pinion seal at fault. The pinion seal is where the driveshaft/propshaft attaches to the differential. The cover seal is the gasket between the metal cover where the filler plug is and the differential casing itself.