Working Differential For RC car

This is the differential that i made for a project that i have going on. I'm making an rc car with as much as possible 3d printed parts. I found this to be a difficult part to start with and figure out how to make it wich is the same for the other people out there that are doing the same project as me or maybe you can just print this to figure out how a real differential works.

YOU NEED 4 BAIRINGS: OUTSIDE DIAMETER,18   INSIDE DIAMETER,12    LENGHT,4 

You can modify the drawings to make your bairing's fit.