The JB "big diff" debate

redzone · Post by **redzone** » Mon Feb 17, 2014 11:23 pm

After finally firing up my microfiche reader (cheers to Panda for that one) and inserting my complete set of JA-JD Starion parts microfiche, I had a look at the part numbers for the diff carrier assemblies for each model. I found NO evidence that anything other than the small diff was fitted to JB models. There is no break point (chassis number or date) mentioned for a changeover as would be found if they changed mid-run to a different sized differential.

Here are the part numbers for each carrier (housing) assembly.

JA (open diff small housing) MB160365

JB (open diff same housing as JA) MB160365

JB (lsd diff same housing as JA) MB160365

JD (open diff large housing) MB290945

JD (lsd diff large housing) MB290945

If there was ever a JB that left the factory with a large housing, it would have a break point mentioned and the MB290945 p/n would be mentioned..... But it's not! :beer

JDSTAZ45 · Post by **JDSTAZ45** » Tue Feb 18, 2014 3:51 pm

Nice one RZ!
Well, there you go! JB's should all have small diff housings.
For whatever reason, JB #219 had the large diff housing and one other I was aware of....
What threw me off even more...was that later model GSR-V's 1986-88 have small diff housings!

popup · Post by **popup** » Wed Feb 19, 2014 8:39 am

...And if its any use (as I know some of the UK cars got exported):

MB160365 1982.02.1 to 1984.05.3
MB290945 1984.06.1 to 1988.05.3

and the 2.6 all got MB290945

ProZac · Post by **ProZac** » Wed Feb 19, 2014 6:47 pm

Good info!

Did any Starions fitted with the big diff have a ratio different to 3.54:1, from the factory? I've never seen or heard of one, but I've seen small diffs in both 3.9:1 and 3.54:1 from the factory.

ProZac · Post by **ProZac** » Wed Feb 19, 2014 6:48 pm

Popup - Where did you find that info, if you don't mind sharing? I love looking up stuff like this :-).

JAS · Post by **JAS** » Thu Feb 20, 2014 9:56 am

Ive got a starion big diff gear set of 3.9:1 for my gold car. Got it from a guy that bought it in from the states though. Most of the big diffs Ive seen are 3.54:1

MrBishi · Post by **MrBishi** » Thu Feb 20, 2014 11:56 am

ProZac wrote:Good info!

Did any Starions fitted with the big diff have a ratio different to 3.54:1, from the factory? I've never seen or heard of one, but I've seen small diffs in both 3.9:1 and 3.54:1 from the factory.

JD had 3.9:1 big diffs factory presumably to get over the new asthmatic unleaded motor for 86/7. This may be an Australia only specification.

Neil · Post by **Neil** » Thu Feb 20, 2014 12:33 pm

MrBishi wrote:JD had 3.9:1 big diffs factory presumably to get over the new asthmatic unleaded motor for 86/7. This may be an Australia only specification.

Yeah, my JD has a 3.9:1 and yes it was to try and help keep performance with the drop in power due to the switch to unleaded.

Post by **Alspos** » Thu Feb 20, 2014 3:17 pm

How to tell the two apart

Big and small side by side

popup · Post by **popup** » Fri Feb 21, 2014 3:00 am

Prozac, I'll send you a PM

GasJA · Post by **GasJA** » Mon Mar 03, 2014 1:53 pm

Off topic

Redzone and others

As you have the microfiche do you source any parts for the Starion using www.amayama.com

Another site I was put onto was the Russian catalogue (of no interest if you have access to a microfiche)
http://www.auto-parts.spb.ru/cat/mi/mi2.mycat

On Amayama it shows the two diffs in AUD
Mitsubishi MB160365 530.37 10 Japan
Delays possible: 5% Add to cart

Mitsubishi MB290945 434.95 10 Japan
Delays possible: 5% Add to cart

Amayama still show parts like brake rotors as still being available from Japan.
Is that the only place you can get new brake rotors these days?

The good folk on www.pajerio.com put me on to amayama as it is way cheaper than Aussie dealer parts.

redzone · Post by **redzone** » Mon Mar 03, 2014 3:47 pm

Those part numbers I listed are only the housing, not the complete diff, that's why they are so cheap! I'll look into amayama....

GasJA · Post by **GasJA** » Mon Mar 03, 2014 5:04 pm

Looks cheap yes.

From the Russian catalog and Amayama
34033A CARRIER,RR DIFF
Mitsubishi MB241993 3 705.14 10 Japan Delays possible: 5% Add to cart

looks like that torque tube shaft that wears is still available
Mine clunks when I start to reverse(I think???)

33142 SHAFT,RR AXLE EXTENSION
gives two part numbers both available
Mitsubishi MB160582 270.14 10 Japan Delays possible: 5% Add to cart
Mitsubishi MB290597 268.90 10 Japan Delays possible: 5% Add to cart

I have actually never sourced anything off Amayama myself. Just wondering if anyone has used them?
I have wasted a lot of time checking prices though.
The Russian catalog is handy for my DIY efforts, as every part is shown in the blowups.

ProZac · Post by **ProZac** » Tue Mar 04, 2014 10:54 am

The online rips of the ASA catalogues are pretty handy, I use http://demo.saleepc.ru/mitsubishi, and find it quite helpful.

GasJA · Post by **GasJA** » Tue Mar 04, 2014 11:56 am

Hi ProZac
Great link. Starion comes up as a Japanese model RHD I assume.

The link I posted above comes up with similar diagrams that you can save as gif files. If you want to print those gif files out you need to stretch them in paint by a ratio of 3 to 1.

Have you used amayama at all?
Just wondering if clunk in reverse could be caused by that torque tube shaft wear or diff preload?
I changed the bearing in the torque tube and fitted new universal joints not that long ago.
Get into car and start car - select reverse gear - release foot off clutch = clunk.

Austarion

The JB "big diff" debate

The JB "big diff" debate

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