Buying a new Team Durango 2WD gear cover is out of the question now - or if you find one it's priced like Unicorn-Poop. So I modelled one up. It fits the original gearbox plate perfectly and wraps over the edge (unlike the original). But depending upon your gearbox configuration RM3/4 or MM3/4 you'll need to remove part of the edge-wrap just where it might foul the suspension pin holder.
My 3D printer isn't a new one, and I've always had challenges with suppot material so one file has modelled support at 0.5mm thick and 1mm spaced (there's a 0.2mm breakable gap between the support and the print in most areas). One STL requires your slicing software to generate the support, and the other has the support already in place. First version off the printer works fine on the DEST210 I'm putting together from parts - including a non standard finned motor plate.
Let me know if you'd like to see any tweaks
Reprap Pro Mendel Tricolour