"Note: Images are for illustration purpose only. Actual product may vary."

https://cimg1.ibsrv.net/gimg/www.rx7...e83c085756.jpg
I wouldn't get too wrapped around the photo.

Yeah I'm 99% sure that's a generic picture, that actual part is for a different car.

Dale

I’m in the middle of swapping my 4.44 set. Figured I would keep the forum open while i did this, did not expect this thread to be alive today :lol:

anyone have any alternate aftermarket part numbers for the LSD/carrier bearings; Timken, etc.?

Asking for someone else on RX8Club.

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so maybe this is a dumb question, because I always thought that a ring and pinion had to be designed for each other as a specific pair. But I see a pattern wrt tooth counts on the short pinion 8” ring gear sets

3.583 - 12/43*
3.727 - 11/41*
3.909 - 11/43
4.100 - 10/41
4.300 - 10/43
4.444 - 9/40
4.777 - 9/43
5.125 - 8/41**
5.375 - 8/43**
5.857 - 7/41**

* first two are 929/MPV//B2600 ratios from 1980’s-1990’s
** last three a guy from AU sells on eBay

So if these were all loose in a box would you be hosed trying to figure out which pinion goes with which ring gear or are some of them actually interchangeable in some way? It seems like too much of a coincidence for a 41 and 43 tooth count to be so prevalent, and the 40 tooth gear being the odd one out.

Usually the matched pair have markings, if you were trying to find them in a mixed box of bits - end of the pinion and on the perimeter of the crownwheel.

I have heard of people replacing one or the other in the same ratio without issue, production hobbing nowadays to thank no doubt there! Wouldn't be too keen swapping between though - interesting mesh I'd expect, even if numerically the same. Seem, to recall that bloke, if it's who I think it is, was using Kia truck ratios for the, rev the ring out of it ones.

Do have all the bearings for diffs elsewhere, but still locked down at the moment. The better bearing houses did have cross reference books for virtually everything 15+ years ago, FDs included, imagine it's all online now?

They have markings, but my recollection is fuzzy on if they match up or not. I’ll have to go double check on that.
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I’ll be pulling the numbers/codes off a few R&Ps soon, some of which are the early 1980/90 smaller pinion bearing version that have to be sleeved for fitment in the FD/RX8 “P” differential. Maybe someone might be interested in doing a detailed differential thread similar to the recent transmission thread? I’ll try to document with pics as well.

shoot me a PM, lets do it

along these lines i wonder if there are some differences in the P Type housings or maybe gear pitches or something, or maybe this is the spacer thing you mention. possible the later ones have the spacing machined in (or out)
or perhaps the Rx7 and 8 get a different/better material or something

https://cimg7.ibsrv.net/gimg/www.rx7...89c6a1eb78.jpg

^^hey sorry, just haven’t gotten to documenting the R&Ps I have yet, but hopefully soon. I’m not sure about that, wondered myself, but am going to find out. The earlier diffs had the threaded side adjusters, so I’m open to the idea that a shim or machining of the ring gear may be necessary. A few people on here did it back then and never reported any issue though.


Also, not seeing any listed on the forum, so thought I’d ask if anyone has a 4.10 gearset they want to sell? please pm me.
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just a final check; found one off the forum, but more trusting of and preferring to buy one from someone on here

Dale, thanks for starting this thread and sharing info years ago. I have been considering this final gear upgrade for some time and recently started looking for a donor RX-8 diff.

From online research through the RX-7/RX-8 forums and Mazda sales brochures, it appears the following final drive ratios were available on the RX-8. Can anyone confirm?

4.30 - From 2004-2011 Automatics without LSD
4.44 - From 2004-2008 Manuals or Automatics with Sport Package/LSD
4.77 - From 2009-2011 Manuals or Automatics with Touring/Grand Touring Package/LSD

Ideally, I would go with the 4.30 from the RX-8 base model automatic trans.

The 4.44's are so common IMHO I don't see a good reason to find the 4.30's. There's also a very minimal difference between the two.

Highway cruising is comfortable and at a sane RPM and you do get a nice kick of extra acceleration.

Dale

the 4.300 was only 2009 - 2011 Automatic RX8

it’s often mistakenly listed for earlier RX8 Automatic models, but they had the 41/9 4.444 ratio same as the Manual RX8s for both the early 4-spd and later 6-spd Auto S1 models, at least for USDM

from the 2004 RX-8 Service Highlights Manual:

https://cimg0.ibsrv.net/gimg/www.rx7...4d5dd4191.jpeg



From the 2009 RX-8 Service Highlights Manual, also indicates the 2008 MY to show the Change:

https://cimg5.ibsrv.net/gimg/www.rx7...3f82867f7.jpeg

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interesting, the parts catalog shows high power a/t with a 4.3, and that should be the 2006-2008 cars.
https://cimg3.ibsrv.net/gimg/www.rx7...7c5f1d9296.jpg

Maybe I’m the one who is mistaken then. Because I always thought the early 2004-2005 4-port was 4.300 for sure, and honestly was never sure on 2006-2008 for the 6-spd auto.

However my parts documentation is most likely inferior to your own and I don’t even see the 4.30 gears listed any more for those model years, just the 4.444, coupled with the other documentation from Mazda. Errors in such documentation is not uncommon though and perhaps there’s a subsequent correction memo that I don’t have. :dunno:

the 2004-2008 catalog is a little tricky because it does all of S1 in one catalog, which is unusual for Mazda. the counterpoint is the FD, it has a separate catalog for 93, 94 and 95.

next step would be to go look at autotrader and run some vins through the EPC and see what it comes up with. its possible i'm interpreting the catalog wrong, it would be nice if they had the dates, that would be a simple way to tell too

it looks like this,
https://www.autotrader.com/cars-for-...ckType=listing

at work we'd run a bunch of vins...
https://cimg9.ibsrv.net/gimg/www.rx7...fa3ff3e9fa.jpg

ok, schooled me again :dunce:

I’m still trying to get to the 8” R&P identifications, seems like there is always something else in the way, but just received another one to catalog as well.

i'm amazed on such an old car that there is still stuff to learn, its kind of neat actually.