Lets start with the rear motor box, which covers the wheel (traction) motors. For a complete box, four parts are needed.
1. Parts motor box lid (traction motor) right/left. Right printable without support, left minimal support needed (100% overhang threshold). The mounting holes for chassis damper must be completed with an drill.
Motorbox left: I added a mounting hole for a switch (its a keyed switch) with an diameter of 22mm. If you don't need this switch here, just print the normal Motor box.
Motorbox right: I added mounting holes for a DC Plug and one for a control light (RAFI). The diameter of holes are 12mm and 10mm. If you don't need them, just print the normal Motor box from Robin Fröjd
All parts available at Thingiverse.com https://www.thingiverse.com/thing:3344829