Summary

Axle with ball diff
Uses the Ursa Bear hubs
Locked hubs to use it as a back axle, will make straight axle end to go with it soon.
Ball diff the same as my other one, just different https://www.thingiverse.com/thing:2826921

Started making a hub, but found the hub from the Ursa Bear fits. Maybe I'll finish mine one day. Some of the other parts have evolved from from it.

Not tested in use yet.
4x12x18 Bearings x4
Thrust bearing https://www.banggood.com/XLPOWER-520-RC-Helicopter-Parts-Tail-Thrust-Bearing-Set-p-1229065.html?rmmds=mywishlist&cur_warehouse=CN
3mmx20mm cap head bolt
2mmx? need to measure x6
.177 cal BB's 4.5mm for the balls in the diff
2x washers 21.68mm x 1.14mm (don't need to be exactly the same)

Narrower and wider diff, but not as finished as this one. I'll add them later.

Updated to proper axles.