WTB: Miata Diff Housing
Thread Starter
Joined: Apr 2009
Posts: 7,174
Total Cats: 180
From: Arizona
Need a 1.8L open miata diff.
Do not need the aluminum part that has the mounts. Just the pumpkin.
Do not need the aluminum part that has the mounts. Just the pumpkin.
Last edited by FRT_Fun; May 9, 2011 at 10:20 AM.
Thread Starter
Joined: Apr 2009
Posts: 7,174
Total Cats: 180
From: Arizona
The Iron section I believe, the part that connects to the drive shaft. Not the part with the diff mounts. I don't have any differential right now because I sold my KAAZ.
Thread Starter
Joined: Apr 2009
Posts: 7,174
Total Cats: 180
From: Arizona

Correct me if I'm wrong, but I need to bolt my RX7 diff (clutch type/3909 r/p) to a miata carrier.
So I need the "E" part (in picture above) from a miata. Then bolt the RX7 internals to it, and then bolt that to the other half of the RX7 differential.
The picture above is what I"m working with.
You need a miata pinion housing, pinion gear and ring gear. You'll bolt the miata ring gear onto that rx7 LSD, then drop it into the miata pinion housing. Backlash will need to be adjusted. Then close it up using the pictured aluminum section with miata diff mounts, or your miata one.
so to sum up:
this is all you need from your RX7 rear:

the acutal LSD, and the stub shafts.
You need to bolt on a miata ringgear that matches the pinion:

You then need ot fit it into the miata housing:

then you need to adjust your backlash, cover it up, and bolt in.
so to sum up:
this is all you need from your RX7 rear:

the acutal LSD, and the stub shafts.
You need to bolt on a miata ringgear that matches the pinion:

You then need ot fit it into the miata housing:

then you need to adjust your backlash, cover it up, and bolt in.
Thread Starter
Joined: Apr 2009
Posts: 7,174
Total Cats: 180
From: Arizona
Wait wait, so I need to use the maita ring gear? I can't use both the RX7 ring and pinion? **** *****. I'm trying to follow this:
When it says decide what ring and pinion to use I figured it meant, use either the miata one or the rx7 one. I'm trying to use the 3.909ness of the RX7 diff.
Open the RX7 assembly. Decide what ring and pinon to use. Bolt the correct ring gear to the RX7 LSD. Swap the pinon gear and lsd guts to the miata pinon housing. Set the backlash (and pinon depth if swapping pinon gear), and assemble the miata pinon housing to the RX7 housing. Drill out the RX7 diff bushings and push in miata specfic bushings. Install as normal.
Thread Starter
Joined: Apr 2009
Posts: 7,174
Total Cats: 180
From: Arizona
Well **** that description blows. I realized how long the pinion housing was but I don't know what magic was under it that made it that long.
So my hope of having a 3.909 is lost?
And **** stub shafts I'm getting the RX7 circlips and using my miata axles.
So my hope of having a 3.909 is lost?
And **** stub shafts I'm getting the RX7 circlips and using my miata axles.
use miata circlips with your miata axles.
It's possible you can use that rx7 ring gear and your miata pinion....I have no idea if it will work or not. It is possible to use the rx7 pinion gear from a 84-85 sold rear axle unit, they had the same sized pinion gear as the miata. Just need a different seal/bearing for them. IIRC y8s did this in his rear.
But I have a feeling that ring gear is the same with 43 teeth and it's the pinion with 11 teeth that drops it to 3.909
It's possible you can use that rx7 ring gear and your miata pinion....I have no idea if it will work or not. It is possible to use the rx7 pinion gear from a 84-85 sold rear axle unit, they had the same sized pinion gear as the miata. Just need a different seal/bearing for them. IIRC y8s did this in his rear.
But I have a feeling that ring gear is the same with 43 teeth and it's the pinion with 11 teeth that drops it to 3.909
Thread Starter
Joined: Apr 2009
Posts: 7,174
Total Cats: 180
From: Arizona
use miata circlips with your miata axles.
It's possible you can use that rx7 ring gear and your miata pinion....I have no idea if it will work or not. It is possible to use the rx7 pinion gear from a 84-85 sold rear axle unit, they had the same sized pinion gear as the miata. Just need a different seal/bearing for them. IIRC y8s did this in his rear.
But I have a feeling that ring gear is the same with 43 teeth and it's the pinion with 11 teeth that drops it to 3.909
It's possible you can use that rx7 ring gear and your miata pinion....I have no idea if it will work or not. It is possible to use the rx7 pinion gear from a 84-85 sold rear axle unit, they had the same sized pinion gear as the miata. Just need a different seal/bearing for them. IIRC y8s did this in his rear.
But I have a feeling that ring gear is the same with 43 teeth and it's the pinion with 11 teeth that drops it to 3.909
So is this part in the FAQ wrong too then? I already have miata circlips on my miata axles.
probably a lot of it is still wrong 
the circlip fits the axle...the rx7 shafts have a smaller grove in them and require a thinner circlip. a miata circlip on an rx7 axle wont fit into the dif, a rx7 clip on a miata diff wont lock the axle in place.
the mention of using the rx7 pinion was when i still had info on using the 84-85 rear in there. thats the only rx7 pinion that works, and there is some undocumented things you must do in order to make it work. Ask y8s about it. I'm sure you could find one cheap.
like this: 1984 Carrier Mazda RX7 3.90 $50 Agee's Auto Parts USA-VA(Christiansburg) 540-382-2477 / 800-678-6901
still you need to put that into a miata housing, since the rx7 housing doesnt have PPF mounts.

the circlip fits the axle...the rx7 shafts have a smaller grove in them and require a thinner circlip. a miata circlip on an rx7 axle wont fit into the dif, a rx7 clip on a miata diff wont lock the axle in place.
the mention of using the rx7 pinion was when i still had info on using the 84-85 rear in there. thats the only rx7 pinion that works, and there is some undocumented things you must do in order to make it work. Ask y8s about it. I'm sure you could find one cheap.
like this: 1984 Carrier Mazda RX7 3.90 $50 Agee's Auto Parts USA-VA(Christiansburg) 540-382-2477 / 800-678-6901
still you need to put that into a miata housing, since the rx7 housing doesnt have PPF mounts.
Thread Starter
Joined: Apr 2009
Posts: 7,174
Total Cats: 180
From: Arizona
Holy **** okay. Thanks for the heads up brain I would be pissed to find this **** out after buying stuff I don't need/not all the stuff I need.
So.... WTB: MIATA OPEN DIFF
So.... WTB: MIATA OPEN DIFF
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