DIY Diff Shortening

[gearb0x]

Hey guys,

I was just wondering if anyone had attempted to do anything like this them selves before

I'm looking at either a Torago YR22 or MS112 diff for my autocross car (AE71) which are 20mm too wide either side, I would like to keep the stock width so I can stick to cheap toyota alloys/ma61 wheels



The above picture is a YR22 diff with AE86 mounts welded on. Apparently the stock axels have around 15-20mm extra spline which can be shortened down quite easily.

The housing it self seems to have the outer tubes "flared" then press fit onto the center housing where the green/red marks are. What i was hoping to do was to be able to grind back where the red circle is, then cutting the right length on each end of the green marks (on the inner tube and outer tube) then putting it back together again, jigging it ( too keep it straight) and welding.

Are the tubes a press fit? will i need a 40 tonne press to get them apart? Am I insane? Any input would be greatly appreciated

Regards,
Phillip Savage

[3jcelica]

Yeah I have done similar, I cut the tubes out of my old diff and welded all the mounts onto a different centre housing and bearing retainer so two joins on each side. This was for a track car. I would go a different route for a road car. Has stood up to some good abuse for a year, no sings of issues. I did mine in a jig to keep it all striaght.

Do you need to shorten the housing and axles though, 20mm either side could be made up with say FWD wheels (which are very cheap) and some guard flaring I would suggest.

I use a r31 diff which is quotes some where between 1450-1470 on a ke70. I belive the yr22 or ms112 diff are around 1450 ?. This will fit under with the MA61 wheels (I belive they are 6.5") and some good guard flaring.

[gearb0x]

I have thought of going the FWD offset route which was my original idea as my front track is currently increased by alot.

But it has caused problems with bump steer, and i managed to find a T-18 front brake setup with volvo 240 disks/callipers for cheap which will put the front end back to stock width +6mm for the rotors

meaning Ill have to mix and match wheels when id rather just have the same wheels all round

[gearb0x]

any pictures of your jig setup?

[thechuckster]

I'd suggest cutting out near the end of the tubes (at the bearing retainer) so any misalignment isn't amplified.

[CLG]

This is also how they shorten diffs at the local shops:

Got the boss to machine the alignment jig at work

[3jcelica]

I have seen those jigs and they are very good for shortening. My jig was a little different as I was not shortening. Mine consisted of a u shape that bolted up both bearing retainers and the pinon. I bolted the diff in and then cut the diff up. hence bearing ends sat in the correct position relative to the crown wheel. Note the jig was made off heavy RHS i think 100x100x6mm. Worked well for me but if I was shortening I think the only way to do it would be a jig like above