R180 Differential drain/fill thread size

[Jeff Berk]

Does anyone know the threading size for the differential drain and fill plugs. I tried to measure them and came up with 27x2.0 but apparently this was incorrect. My "Thread Detective" doesn't go this high.

[CanTechZ]

12 minutes ago, Jeff Berk said:

Does anyone know the threading size for the differential drain and fill plugs. I tried to measure them and came up with 27x2.0 but apparently this was incorrect. My "Thread Detective" doesn't go this high.

Not near my car right now, but 27 x 2.0 sounds very close to SAE 1.0625-12UN thread. A common size for fittings

https://www.machiningdoctor.com/threadinfo/?tid=120

Edited April 15, 2024 by CanTechZ

[siteunseen]

Says here 1/2 NPT...

https://www.zdriver.com/forums/240z-260z-280z-s30-forums-9/transmission-differential-drain-plugs-37496/

[Jeff Berk]

I wonder if it's actually 1/2-inch BSPT? They are almost interchangeable.

If it is 1/2-inch NPT I should have one locally available.

[Yarb]

@Jeff Berk, Are you trying to do something that’s not Stock? If so I totally understand. If not why not go to the local Nissan dealer with a p/n from CarParts Manual and order what you need. Forgive me here if I missed something.

[Jeff Berk]

10 hours ago, Yarb said:

@Jeff Berk, Are you trying to do something that’s not Stock? If so I totally understand. If not why not go to the local Nissan dealer with a p/n from CarParts Manual and order what you need. Forgive me here if I missed something.

This is related to a project on another thread. I'm having a custom diff cover cast and need to tap it to accept the OEM plugs.

[Yarb]

Sorry about that. I totally didn’t put two and two together.

[Captain Obvious]

My understanding is that the tapered hardware used elsewhere on the Z's is BSPT. So my expectation is that the original plug on the diff is BSPT as well.

That said... I sure wouldn't fault you if you decided to use NPT instead of BSPT for a full custom part of your own design. I probably would.