So I have made plenty of vehicles, all of which had working shadows.
This one however doesn't for some reason. I can cast shadows on it just fine, it just doesn't cast any of itself.

Shadows also aprtially go through it, as if it was water:

Any help would be appreciated.
EDIT: it acts as if it has minimum shaders on, so the sides not lit by the sun ARE in fact darker than the ones lit by the sun. Weird spaghetti torque going on.