I noticed while changing the bottom shock absorber bush that the pinion nose of the diff was slightly oily.
I don't know how long it's been there.
I got the car after it's 80K service so it could be oil from topping up or level checking or it could be the oil seal.
I'll check diff oil level, of course, but if that's OK can I clean the oil off and see if it comes back before changing the seal or is a failure likely to be catastrophic?
My experience of oil seals (and there's no oil pressure here I assume) is of gradual wear but I don't want the diff seizing.
The car has stood for two weeks and there's not a drop of oil under it.

 

Slightly/a little wet isn't that bad (actually it prevent some rust here and there ;-)), but the pinion is known for leaking, and can be relatively easy repaired (if needed, don’t know without checking the oil level when you need to though). One thing to watch out for is the air vent on top of the diff, if that one gets clogged, you do get positive pressure inside the diff, causing leaks.

 

Thanks, Avos, I had a mental picture of a vent when I said 'no pressure' but I will certainly check it.How hard is it to get at?

 

Not sure, I have never tried it. It looks tight, but maybe with the right type ratchet it might be doable for the patient.