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Rear gear set for quaife diff


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I noticed a few drops of gear oil inside my rear left rim while I was unloading the car from about a 2 month winter nap. Looks like I'm doing axle seals, and figured while I'm in there I can change the gear set too. 


The car is 2003 birkin, any guesses on what Toyota live axle rear end assembly they were putting in them back then? Or just a quick measurement to see what it is from the sides?  


I have a couple photos from when I had the tray out too. 


Thanks all. 





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Thanks, you seem pretty confident on that one! My paperwork shows a quaife diff in there, so I'd imagine I can find another gear set for it. And that page had all the bearings and seals. I wonder why the previous owner thinks it's a Hilux rear? 

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Articles on the birkin mention a toyota axle and maybe they switched to that at some point. If you go to quaifes site, they list a diff under the caterham as a BW68 plus the ridges on top of the housing make it unique. Are you looking for a more highway friendly, numerically lower ratio?

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If you look at my previous post history I was looking at changing the gear set in my t9, it is geared very high. 2.39 first. And I was leaning more toward a 4.30 or 4.56 rear gear versus my current 3.90 to get some more bottom end pep. 

I'll go look at the quite site now, thanks again. 

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I think it would hard to find if it was ever available for such a small diff. Part of the problem is that as the numerical ratio increases, the thickness of the teeth decreases while at the same time the multiplied torque increases. You might consider an axle conversion to an equivalent that came with a 4.30 ratio (maximium), like the Toyota 10 bolt 6.7" ring gear axle used in dwarf cars, just not severely shortened on the right side. For a used axle, look at 82 and older corona, 84-87 corolla GTS, 74-79 SR5, 71-85 celica ST and GT. I expect there are parts available for these for racing. They came with either two or four spider gears and an open or limited slip.

A Ford 8 inch is a common axle here that is built like the famous ford 9 inch only smaller and lighter. I think it was used in the H&S Seven.

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Hi all.  I built my Birkin from the basic "BIY" kit in 2000/2001 and it has the same axle as Redbeard's.  I installed a Quaife in my rear axle when I built the car.  Quaife has a specific listing in their catalog for the solid axle Birkin from that era.  We were told by the Birkin factory in South Africa that the rear axle was a newly manufactured unit as used in a Toyota Hilux minivan manufactured and sold in South Africa.  The only ratios I have ever known of for those rear ends were the two that came in solid axle Birkins.  4.11:1 until early/mid 2000, then 3.89:1.  My kit landed in the US in September of 2000, and it has a 3.89. 


The first two pics below are the original diff carrier that came out of my Birkin, replaced by the Quaife.  If you zoom in on the first one you will find the number "68" in the casting.  Hmmm.  MV8 - where did you get the info that this is a BW axle?  The axle housing castings do not have the name Borg-Warner in them, fwiw.  Also, the rear cover looks different than one in a pic on that page you linked.  The pictured one is deeper.  This is fascinating. 


Incidentally, the Quaife catalog still lists Birkin as "Quaife Borg Warner M68 Axle ATB Differential".  It also says "In Stock" which is shocking!:




Their listing has a link to a "technical spec" drawing.  I dug up the old diff center section, and the dimensions and spline count of my old one appear to match the current Quaife drawing.  So, maybe we all missed the boat years back - I have never seen the Birkin diff identifed as a Borg Warner - Quaife's catalog in 2000 made no mention of Borg Warner in relation to this diff. 


In late 2000, before I dropped the big bux on a Quaife, I sent one of these center sections (borrowed from the importer Dick Brink) to Toyota Racing Development in California on the off chance they could identify it and provide a more cost effective LSD.  They passed it around to their engineers, and nobody had ever seen one like it.  Maybe it being a Borg Warner explains that. 


FWIW, the Quaife is a fantastic unit.  I consider it table stakes on a solid axle Birkin.  I drove one with an open diff and it wouldn't put power down at all.  And the Quaife install was a breeze - no change to the setup and the gear pattern was perfect.


Please share whatever info you dig up!  This is of great interest.


I just replaced an axle seal on my Birkin - Tom gave me the part number - it's a Timken 472826.  I got them at a local bearing shop.


Happy Motoring!






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1 hour ago, BirkinBernie said:

MV8 - where did you get the info that this is a BW axle?  The axle housing castings do not have the name Borg-Warner in them, fwiw.  Also, the rear cover looks different than one in a pic on that page you linked.  The pictured one is deeper.  This is fascinating. 



The housing ribs on top of the center section are unique to this axle but I agree, the cover is shaped a little differently for the datsun axles pictured. It may be different for the toyota van applications.

I suspect there was some sort of trade agreement with Datsun and Toyota in order to sell their products in South Africa that was satisfied by locally sourced axles.

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Based on what you want, I'd consider shelving the existing axle as-is and adapting a 90's or newer suzuki sidekick/geo tracker rear axle for several reasons.

The pros:

1)      The width should be close to what you need as-is.

2)      The ring gear is a bit larger than the m68 for stronger gear sets (6.7" vs. 6.9")

3)      This axle comes with 4.30, 4.62, 5.12 and 5.37:1 gear sets (4.62 strongest with the fewest ring teeth).

4)      A torsen type diff is available for about $650.

5)      Despite being considered weak for a 4x4 with very large od tires, it should be a little stronger/heavier than what you have.

6)      The drop out diff carrier/pumpkin is easily setup on a bench.

The con: The axle uses a very large, common 4x4 truck 5 bolt circle and hub but adapters are available. The adapters would increase the axle width about two inches.


I have a 90s 2 door, 2wd convertible tracker I converted to an s10 v6 and 700r4 with an open 5.12 axle and 235-60-16 tires on grand vitara wheels. Let me know if you'd like any measurements. The 90's axle is a three link where the 99 and newer is a 4 link with a panhard bar, but you'd be cutting everything off to duplicate the birkin brackets.


This is my installed axle and my 4.30 diff with a couple web pics of the axles.

. 041.jpg

04vitara axle.jpg

90s tracker axle.jpg

. 159.jpg

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