Mini-Z Box Stock Racing Series Part 5: Gear Differential

[@fwfefrtefdv4719]

Hi, I have lost the small black nut fit behind the rear left wheels slot (4:49) in your video. Can I use a bearing to replace it? Or are there after market part available? 4:49, Thanks

[@Slacking02]

Why did you use the 15k over the 30k?

[@AMM0394]

There was still diff action with the 15k. Need thicker? Or more?