2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

3.9 LSD 3rd member????

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Old Aug 17, 2002 | 10:31 PM
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3.9 LSD 3rd member????

Is there such a thing?? I thought ALL LSD's were 4.1!

Only thing I could imagine would be a S4 GXL with automatic transmission.

Ok, you brain trust out there. Please share your knowledge 'cause I'm by a thread in the 2nd Gen parts section.

Thanks.
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Old Aug 17, 2002 | 10:35 PM
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No such thing unless you put a 3.9:1 ring and pinion into an LSD.
They didn't come stock. LSD's only came on certain manual cars.
If that car was an automatic, it got a 3.9:1 open diff.

Although I bet jspec automatics had LSD seeing how they were all turbocharged.

Last edited by Node; Aug 17, 2002 at 10:38 PM.
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Old Aug 17, 2002 | 10:42 PM
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I thought all TIIs were manual?
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Old Aug 17, 2002 | 11:30 PM
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Originally posted by DCmina
I thought all TIIs were manual?
Not the JDM TII's. They come in manual and auto. Why?????? I dunno....
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Old Aug 18, 2002 | 12:40 AM
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84 and 85 GSL (and GSL-SE, i believe) had 3.9 gears and a LSD. And you could always bolt on a LSD to a 3.9 FC diff.
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Old Aug 18, 2002 | 01:36 AM
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We need owners of an AT s4 GXL to step forward. By the standard rules, being a s4 GXL it should have LSD; being an auto, it should have a 3.9.

You can test for LSD by spinning the wheels while off the ground, and you can test for ration by pulling the speedo gear adn looking at its color. I have never run across an auto tranny that had the gray gear, which is 4.1 They all have orange gears, which is 3.9. Matter of fact, I worked on a couple of AT GXL's back a year or so ago, swapped tranny on one of them, and IIRC it has the organge 3.9 gear, though I didnt test it for LSD. But then I remember working on another AT GXL, and it had an LSD tag.

SO I believe, unless someone proves me wrong, they had 3.9 LSD's.
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Old Aug 18, 2002 | 01:43 AM
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I saw a s4 GXL automatic with the LSD tag on it as well, I thought someone just stuck it there for looks, but it quite possibly could have been there (as it was all dirty and didn't look like it was placed there at all, hell never looked like that bolt was removed) Time to head back to the junkyard where I saw it and take it home with me
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Old Aug 18, 2002 | 02:33 AM
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Exclamation a s4 GXL it should have LSD; being an auto, it should have a 3.9

This is exactly why I was asking.

My factory brochure lists LSD on GSL's as Standard equipment. Where as it lists having automatic transmission an Option. It also indicates A-4 (Automatic) as 3.909 "Final Drive".

So, it appears there are such a thing as 3.909 LSD's. But, it still doesn't seem right.

Icemark, where are you when I need yah??




Last edited by HOZZMANRX7; Aug 18, 2002 at 02:35 AM.
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Old Aug 18, 2002 | 02:39 AM
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I wonder what it'd be worth to sell a 3.9LSD, any ideas?
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Old Aug 18, 2002 | 03:22 AM
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Hmmm, this would be news to me.
I thought all autos got 3.9 and open diff as it wasn't car dependent for autos

Every RX-7 in Japan was turbo, 1st gens (SA22C) were all 12AT's, FC's were all 13BT, so of course they had to have autos for people who couldn't drive a stick, and yes they have those awesome turbo verts that we all like
And you had better know that all FD's came w/ 13B-REW (twin sequential) stock.


And as for what mazdaspeed7 said, I was talking about in FC's.
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Old Aug 18, 2002 | 08:59 AM
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Originally posted by Flyby116


Not the JDM TII's. They come in manual and auto. Why?????? I dunno....
Because ALL FC's in Japan are TII...unless you special ordered it from the states for an n/a.
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Old Aug 18, 2002 | 10:17 AM
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if you special ordered an NA, than your a loser
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Old Aug 18, 2002 | 12:20 PM
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Originally posted by jspecracer7


Because ALL FC's in Japan are TII...unless you special ordered it from the states for an n/a.
Im just saying "why" about the auto is because I had auto in an N/A though...its the worst thing ive ever driven. Minivans would beat me lol SO SAD! haha
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Old Aug 18, 2002 | 02:04 PM
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Originally posted by mazdaspeed7
84 and 85 GSL (and GSL-SE, i believe) had 3.9 gears and a LSD. And you could always bolt on a LSD to a 3.9 FC diff.
gsl came with 3.9 gslse came im 84 with 4.076 and 85 came with 4.08
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Old Aug 18, 2002 | 03:00 PM
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Originally posted by darkwaveboi
if you special ordered an NA, than your a loser
Drifters are the only ones who I've heard of doing it. For the powerband.
Althouh RE Amemiya's JGTC racecar is a carbureted N/A 20b.....
What losers



Originally posted by Flyby116
Im just saying "why" about the auto is because I had auto in an N/A though...its the worst thing ive ever driven. Minivans would beat me lol SO SAD! haha
Dude, think about it. Not all of Japan is a super sweet dorifto god, or a wangan freak. Some people buy cars just to get to work, or drive to the store. Not everyone can drive a stick.
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Old Aug 18, 2002 | 03:05 PM
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I have an automatic GXL, unfortunately it's wedged in the garage and I can't get to it to jack a rear wheel up to see if it's LSD or not.

You can never trust tags... sometimes people forget to put them back on, and then when working on the next one they find the tag on their rollaway and then put it on another car...
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Old Aug 18, 2002 | 03:09 PM
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Originally posted by Node
Every RX-7 in Japan was turbo, 1st gens (SA22C) were all 12AT's
Most definitely not. I'm fairly sure that the 12AT was optional, and anyways, the first 12AT RX-7s were sold for the '83 model year, some 5 years AFTER the first 1st-gens were made. That's 5 years of exclusively non-turbo RX-7s...
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Old Aug 18, 2002 | 04:20 PM
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Sorry I have been out a town a lot lately.

It is my understanding that all the series 4 Jspec FCs had 4.1 rear ends on the automatics, while the 5 speeds where all 4.3.

Although the 88 sales book claims that the automatic tranny was an option on the GXL and LSD was standard, several other books including The History of the RX-7 claim that no automatics came with an LSD from the factory on North American models. This would follow Mazda's concern about the overweight nature of the GXL in the first place.

I personally have seen up close only enough automatic tranny FCs that I could count them on both hands and have a few fingers left over, and none had LSDs. So I am tending to believe John Matras and a couple of other writers when they say that no NA automatic FCs had LSD.
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Old Aug 18, 2002 | 04:25 PM
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They're so concerned about weight that they'll not put an LSD in an automatic, but they WOULD put a steel hood on the car?
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Old Aug 18, 2002 | 05:09 PM
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The plot thickens

All JSpec S4's with 5 speed manual had 4.3 ratio 3rd members? So, if I were to get a Jspec S4 GXL LSD from a used parts provider in Japan, it would be a 4.3 ratio?

Further, would it follow all S5 n/a's LSD's with manual tranny would be 4.3 ratio 3rd members also?

Thanks for all the responses so far. I like Icemarks answer, especially regarding the above.

But, I'm still waiting for a S4 GXL with Auto to respond and confirm if their 3rd member is LSD at least by checking that both wheels turn the same direction while in the air. Thus avoiding the possible false image of a rogue LSD tag, remote possibility as that might be.

Drive safe.


Last edited by HOZZMANRX7; Aug 18, 2002 at 05:13 PM.
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Old Aug 18, 2002 | 05:45 PM
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There were no J-spec GXLs... all japanese market cars were Turbo II's.

*sigh*... Fine, fine... I'll go out to the garage on Tuesday, un-bury the car, and find out if it has an LSD or an open diff. It's an '87 automatic GXL with the broken apex seal mod.
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Old Aug 18, 2002 | 05:53 PM
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and find out if it has an LSD or an open diff.

You're a prince.

Also, same question with understanding that the Jspec 3rd member will be T2 design. I get a Jspec 3rd member from a 5 speed, it will always be 4.3 gearing?
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Old Aug 18, 2002 | 07:29 PM
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Originally posted by peejay
They're so concerned about weight that they'll not put an LSD in an automatic, but they WOULD put a steel hood on the car?
yeah, but they did do other things, like many of series 4 GXLs (and 'verts) came with the light alloy spare, and all series 4 cars came with the Uberlichet alloy jack assembly. I think the weight issue was more a factor that was a concern when the original design for the FC came out at 3000 lbs, and the engineers went on a crash diet for the car. With an 1.3 liter motor, automatic and the combined gas mileage the car was scary close to gas guzzler tax. Besides as I recall there is only 20lbs difference between the steel and alum hoods. Heck they could make half of that (10lbs) just not using the T2 sport seats

And you are entirly correct that there were no NA powered FCs sold as JDM. Sorry that my comments were not clear.

Last edited by Icemark; Aug 18, 2002 at 07:32 PM.
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Old Aug 18, 2002 | 08:47 PM
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I got my S4 with a flat tire, so it was sitting on the spare. That thing weighs a ton anf a half! Definitely NOT aluminum.

Oh man, that reminds me, it still has a flat, too... :/ It's going to be a pain getting it down off of the jackstands, since it sits so low that I had to jack the car up from the side just to get the floorjack under it.

Of course, things not being simple, the car is backed into a crammed-tight one car garage. surrounded by various Saturn, Mazda, and Subaru engine/tranny parts, and only the FRONT of the car is on jackstands....
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Old Aug 20, 2002 | 01:04 AM
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bump

for peejay's report tomorrow.
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