Gday, I am getting a R31 diff housing shortened at the local shop but they wont do the 4 stud axles cause they dont have the resplining gear. Another shop can do my 4 stud axles but where I want the axles resplined the axle shaft is a smaller diameter, only by 0.6mm.

SO my question is who out there has come across this problem and what are the solutions.

Everyone I have spoken to says I must build up the shaft diameter by either welding or metal spray then latheing it down and resplinging. But this goes against my understanding of axles and how they twist. By heating up the end of the axle, via the welding or metal spray the axle will become hard and brittle loosing its twisting ability.

Sorry for the long winded question but I tryed to explane everything. Thanks for reading

Well that's strange.....

I've re-built a few shortened R31 diff's now & every axle I've seen that's been cut & re-splined has been thicker over the length of the axle than the machined / splined section & needed to be machined back to accept the spline profile.

Are you sure it's a 28 spline axle & not a 25 spline one out of a pintara?

i am thinking pintara

have u got a pic off diff???
i have shortened a vl diff and always wondered if i could have shortened and used 4stud skyline axles.....

are vl turbo and r31 same diffs???

Deffinatly 28 spline out of a 6cyl R31 skyline.

Hay coops, how much do you shorten each side by?


I will try and get pics toomorrow

use long axle as the short one and cut down the long one by 155mm, or by 145mm and have 10mm of the spline cut off the short axle, this will get teh pinion pretty much centred compared to just cutting the 155mm off the long axle

this should get it to the right size for a 1200

the only problem with these axles is you cant cut the short one down, as you need to cut down at least 110mm to get past the under sized part of the axle

demo, you might be able to get some r31 axles cut down to the size you need, but its unlikely that the housing will be the right size in the right places, as you need to use the short r31 axle without cutting it down

Soooo if I had 2 long axles I could have em shortened and they will fit. That will save me trying to get my axles built up. Is this correct

In other words the short axle CANNOT be used UNLESS I somehow get it built up to be resplined

Sorry I am just Trying to wrap my head around this so I get it right the first time.

no no no short axle is used, but never cut down and resplined......simply swap it to the other side and it becomes the new long axle
you can cut 10mm of spline off it to make it shorter, as there is 40mm of spline and only 25mm of it is used

then you cut the long axle down till you get the diff width that you want

only problem i can see you having is that the whole centre will be offset a bit to far if you use an un cut short axle as the long one, as with my diff the whole centre is now offset to the passengers side and the pinion is just off centre towards the passengers side
my diff is 20mm wider than standard 1200 size, so if you took the whole 20mm off the axle you were having resplined that would just push the centre over further
so then hte pinion would be a bit off centre making the tailshaft not straight
but i guess thats how it is in the skyline so it should be ok

Ok pigdog, the penny is dropping.

My short axle becomes the new LONG axle
My long axle gets cut and resplined into my new SHORT axle

My new diff is going to be 10mm wider each side than the standard 1200 ute diff, which should make mine the same width as yours.

I am doing this so I can fit larger tyres and the front and rear track will also be the same. Its out cause of the silvia front disc brake conversion.

Its cool, things are slowley falling into place. Just have so sort out the hand brake once the new diffs in, modify the brake lines to fit and sort out a custom tail shaft

ok if its going to be 10mm longer either side, ive got all the measurements you need to cut it down

drivers side axle tube gets cut down 50mm
passengers side axle tube gets cut down 85mm
long axle gets cut down 135mm

then yeah short axle in the new long side and so on

and then you end up with this