The B310 wagon was sold in Australia with the A14 engine for most of it's production run & was fitted with an H150 differential in 3.9 to 1 ratio. The sedan with it's A12 engine also had the same differential, as did the B210 [120Y] models with the Japanese diff.

The last of the B310 'Sunny Sportswagons' sold here had the A15 engine & these had an H150 differential with a 3.7 to 1 ratio.

There is some conjecture as to whether a spacer [of unconfirmed thickness] is required to install an H150 differential into an H145 rear axle housing. They both use the same diff gasket.

The Datsun 1200's that used the H145 diff came with a 3.9 to 1 ratio [in most models, some wagons seem to have been fitted with a 4.11 to 1 ratio]
For most applications, there is little to be gained by fitting a 3.9 to 1 H150 diff as a replacement for the H145 in 3.9 to 1, however, if you need a taller ratio then the 3.7 to 1 will be an advantage.
This model of wagon was not common even when new, so it might take a little bit of looking to find one. This is one of those times when patience would be a virtue.

At least one of our members has advised that he is running an H150 without a spacer in his H145 axle housing without any problems, yet Pitroad in Japan sell a spacer ring for this conversion, & it's not cheap.

Untill I get an H145 differential to measure against my H150, I am unable to say if a spacer ring is needed or not.

The picture below shows the data plate from a B310 wagon & I think that a similar tag was used all over the world.

The two lines of info that you want to see are the second from the bottom, where it says....
Engine A15[S] (carb equiped A15) & the bottom line where it says...
Trans. Axle. The code HB is the second version of the H150 differential & the number 37 says it has a 3.7 to 1 ratio
HA39, or HB39 would be H150 diffs in 3.9 to 1 ratio.
It's all too easy thanks to Feral & his boundless technical knowledge.


In the first line [Type] the code breaks down as W= wagon & P= A15 engine.
In the third line [Model] the second last character 'M' is the code for Australian models. I have no idea what the last character 'B' indicates.