Does anyone else's diff fill and drain plugs look like this?  I stumbled on the fact many other's and pics in FSM look recessed.  When I searched for replacements, they are not this type.  I'm trying to figure out if this is normal or not.

Have a great Memorial Day!

Diff wise, it helps if (for the lower one) you have the "outie " style as far as getting a wrench on it to take it out, as it points at the transverse link bar. 

What really matters is to put the one with the magnet in the bottom hole. That and having it fit and not leak..... As to what is "correct" factory wise, I leave that to the historians.

Transmission wise I usually see an outie on the fill hole and innie on drain hole. 

Thanks for the info.  I await the historians.

1 hour ago, adivin said:

Thanks for the info.  I await the historians.

Somebody stuck a fill plug in the drain hole, probably because the socket type drain plug is a pain to remove.

Browse through these listings, below, and you'll find a few pictures of the original setup. I don't think that Nissan did any "one-off" plug arrangements.

You should post the replacements that are not of this type just so that people can see them.  Might be an aftermarket guy offering an improvement.

https://bringatrailer.com/datsun/240z/?q=240z

10 hours ago, Zed Head said:

Somebody stuck a fill plug in the drain hole, probably because the socket type drain plug is a pain to remove.

Browse through these listings, below, and you'll find a few pictures of the original setup. I don't think that Nissan did any "one-off" plug arrangements.

You should post the replacements that are not of this type just so that people can see them.  Might be an aftermarket guy offering an improvement.

https://bringatrailer.com/datsun/240z/?q=240z

Odd thing is that the drain plug does have the magnet on the inside, so it's not just a fill plug. The fill plug has no magnet. This car has been in my family since new and I can't conceive when or why the plugs would have been changed out.

Check this out.  Here is a picture of a diff for sale at Whitehead and it has the plugs like mine!  At some point did Nissan use two types of diff plugs?

https://whiteheadperformance.com/product/nissan-oem-4-11-r180-diff-differential-used-datsun-240z-260z-280z-280zx/#

Here's your historian.

@Carl Beck

You can get the plugs (both styles) from Subaru cheaper than from most others.

Pickup trucks used the 4.11.  240Z's did not come with a 4.11.  Nissan might have went with the recessed plug for looks.  They even built a special shield just to cover a bolt head in the back on later cars.  On a truck an ugly square head is not such a big deal.

But, Whitehead is just using the same R180 picture for all of his R180 listings.  So, who knows what's what there.

https://whiteheadperformance.com/product/nissan-oem-3-54-r180-diff-differential-used-datsun-240z-260z-280z-280zx-510/

https://whiteheadperformance.com/product/nissan-oem-3-70-r180-diff-differential-used-datsun-240z-260z-280z-280zx-510/

https://whiteheadperformance.com/product/nissan-oem-3-90-r180-diff-differential-used-datsun-240z-260z-280z-280zx/

https://whiteheadperformance.com/product/nissan-oem-4-11-r180-diff-differential-used-datsun-240z-260z-280z-280zx/

78 280Z with bolt head shield.

Whithead's label implies it's just a stock photo he picked up somewhere.

Edited June 2, 20215 yr by Zed Head

Diff plug removal tool (1/2-inch bar stock)

I guess my point is this is my original diff and it has the square plugs.  We are the original owners of the car.  Trying to figure out why I have these plugs...  

May never know. Maybe it got serviced at some point and the recessed plug got destroyed? Maybe the factory used the wrong plug pr ran out of innies...