Guys,

I will shortly be starting the A15 conversion for my 1971 Dato Ute. It is been suggested by various sources that changing over the diff would be a good idea becuase of the extra power that the A15 has over the A12. Given that I have an older model ute this would probably have the 4.11:1 diff ratio. The suggested upgrade / improvement is the 3.9:1 diff from a Series 2 Nissan Bluebird. Is this an easy, straight forward and cheap alternative?? Any tricks to this????

Daz
Adelaide

the bluebird diff is a h165,like the late 1200 diff,so it'll fit the late housing,but the bluebird housing is too wide to fit.i know someone here in sydney with a h165 diff he's trying to get rid of,so i could call him if you'd like.another alternative is a 3.7:1 diff from a japanese made stanza,but they're getting uncommon.

Apparently the early model utes had the h145 diff. As you said the bluebird diff and the later model utes were both h165 which are stronger, the only difference was the ratios. So the bluebird would fit into the later model ute (probably 1976 onwards).

But will the bluebird diff fit into the early model ute (1971) without expensive mods?? Haven't heard of the Stanza diff being done before but I suppose anything is possible.

Daz

I think what he was saying is you'll need the H165 housing from a late model ute (still 4.1:1), which will bolt into your ute, and the H165 center from a series 2 Bluebird, which will bolt into the new housing.

Do not mix up "Diferential" with "rear axle assembly."
The Bluebird rear axle assembly is not useable under the 1200 ute, but the diferential from it, should be. The 3.7 to 1 ratio was also used in series 1 & 2 Bluebird sedans that came originally with the four speed manual transmision. [I have no knowledge of series 3 cars]

If your ute is fitted with a H156 diff, you will need a diff gasket, a CLEAN place to work, the right tools, &, if you don't know how to do it,..... a workshop manual.
No expensive, er even cheap, mods required.

The common Bluebird S2 Centre is a 3.9 one, found in the sedans. I used to run a sedan 3.9 ratio in my Ute diff. Stewart Wilkins was my source that told me the 3.7 came in the Wagon. It might have been "Auto wagon"..it was a while ago.

I always wanted a 3.7 for my car, so I could reclaim first gear, but it was too hard to find one.

Chris

Dattodude
The series 1 & 2 wagons with 4 speed had a H190 diff, so the ratio is irrelevant as the diff will not fit the ute axle housing.

The 3.9 ratio in a H165 diff center was used in all series 1 & 2 wagons & sedans that came with the 5 speed or Auto.

The series 1 & 2 sedans [only] that came with the 4 speed were equiped with the H165 diff & a 3.7 to 1 ratio.

I do not have a parts book covering series 3 cars, but i suspect that nothing changed.

Cool. Well that answers that question.

Cheers.

It fits. I did a conversion in my old ute it was 1972 and a series 2 bluebird diff fitted staight in with no mods at all. and i think youll find that alot of the utes going around have had the diff changed by previous owners anyway. all mine have. worth just having a look first before just assuming.

Guys,

Thanks for the excellent discussion. Good point on having a look underneath first before assuming anything. Is there an easy way to distinguish between the H145 and H165 set ups?? Do I have to pull the bloody thing out just to find out what it is???

Daz