Whether you are just repairing your diff, or upgrading to metal, this video will show you how.

Here are links to parts used in this video:
https://www.horizonhobby.com/product/... - ARAC3711 - Metal input gear
https://www.horizonhobby.com/product/... - ARAC3710 - Metal crown gear
https://www.horizonhobby.com/product/... - ARAC4023 - Case for metal gears
https://www.horizonhobby.com/product/... - ARAC4061- Case gasket
https://www.horizonhobby.com/product/... - ARAC9937- Diff shims
https://www.horizonhobby.com/product/... - ARA716034- O ring
https://www.horizonhobby.com/product/... - ARAC3140- Internal bearings
https://www.horizonhobby.com/product/... - ARA610044- External bearings

And links to other Arrma replacement diff parts:
https://www.horizonhobby.com/product/... - ARAC3999 - Outputs
https://www.horizonhobby.com/product/... - ARAC4027 - Internal gears
https://www.horizonhobby.com/product/... - ARAC4022 - Stock case / gear
https://www.horizonhobby.com/product/... - ARA311031 - Stock input
https://www.horizonhobby.com/product/... - ARAC4059 - Diff yoke
https://www.horizonhobby.com/product/... - ARAC8011 - Internal pins
https://www.horizonhobby.com/product/... - ARAC9828 - Output washers