Thickened Large Idler Gear for Dual Mode Spring Motor Rolling Chassis

The original Dual Mode Spring Motor Rolling Chassis by gzumwalt is a pretty awesome mechanical toy. the only problem i had printing it was the Gear_Idler_Large which has 2 gear parts. the smaller one has a pretty thin wall (0.4mm) which should print fine with a 0.4mm nozzle but would not slice in slic3r.
i could not get it to slice properly on cura 2.4beta, though people have commented that it slices just fine for them.
as i do not have a simplify3d license - i could not test that as well.