Doing a search it seems that several people have had issues with their diff breathers leaking gear oil. My gasket and/or breather had been leaking, so I pulled out the diff yesterday, and in removing the rear cover, discovered this:

It's a thin metal baffle sandwiched in between two cover gaskets, and it appears to shield the breather outlet from oil slung by the crown gear and carrier, like so:

I don't see it on any parts diagrams. Going to get another gasket (I have one already) tomorrow so I can bolt it back up and reinstall. Just curious.

I have not seen one on a Datsun rear end but I have seen this on the Subaru version of the R180.

Interesting.

On a related note, which diff do I have, the R180 or R200? I've heard R180, but Mr Wick Humble in his Restoring Your Datsun Z Car book seems to think auto S30s got the R180 and manual ones got the R200.

Interesting.

On a related note, which diff do I have, the R180 or R200? I've heard R180, but Mr Wick Humble in his Restoring Your Datsun Z Car book seems to think auto S30s got the R180 and manual ones got the R200.

That's partially true, but only for the 280Z. All 240Z's came with R180s.

Edited June 4, 201212 yr by LeonV

You find those shields in the front R180 diff on the Nissan 720 4x4 pickups.

So, you are saying that is a hint as to the source of his differential?

No, just saying where they were installed on the production line by Nissan. You can buy that item separately from a Nissan dealer and a lot of racers do (or did).

My dad (the car's original owner) wouldn't have added that in a million years on his own. I'll ask him about it. Maybe the diff was dribbling and he took it to a shop and they added it.