4.444 x 1.592. Ring gear mod details?

[Numbchux]

Alright, I'm building a transmission for my brat. Stuff I have:

EA82/L series:
23 spline axle stubs, 1.592:1 Low and case from a Part-time 4WD box
Drive/driven shafts, 1-5 gears, speedo gear from Full-time 4WD D/R Turbo box

EJ:
Center diff and housing from a '93 impreza
Front ring/pinion shaft from a 2004 forester XT (4.444 5MT)


And a Carbonetic clutch-type front LSD

First test fit, don't have bearings on the Carbonetic yet, so I'm using the PT4WD front diff for now:



These are all USDM parts. it'll be used with an adapter plate behind an EJ18.




OK. I've heard many times mention of machining a 4.111 or 4.444 ring gear/crown wheel for this application, and I always imagined it was an issue with the outer diameter of the gear. BUT, after test fitting, I find it's actually the thickness that's the issue.

3.90 on the left, 4.444 on the right:

That difference, at the outer edge of the teeth, measures to about 2mm








I'm looking for some more detailed information from those who have actually done this (pics?) before I show up at a machine shop.

[El_Freddo]

I've not done this, but have seen a 4.11 and 4.44 that have both been shaved to fit the 1.59:1 ratio in. Unfortunately I don't have any pics.

What you need to have shaved is the height of the teeth on the 4.44 until the low range gears no longer foul the crown wheel. Phizinza has done his by shaving the L series low range selector ring and the EJ selector fork. His thread can be found here.

I hope this helps. I'll also try and get a pic of one that's been shaved, it could be some time before I see one though.

Cheers

Bennie

[seagull]

I have done a few now with no issues at all
Lathe , crown wheel
5" grinder with a flat finishing disk ( blue grit paper )

[El_Freddo]

How'd you go with the box build Numchux?

Cheers

Bennie

[AlpineRaven]

How'd you go with the box build Numchux?

Cheers

Bennie

Ditto that - any more pics after machine the crown wheel?
Cheers
AP