I was modding this suspension, only the left side. After that I've duplicated them and this happens. Was modelling in Blender
And it looks like this in blender too? Is it when you add a normal map that it does that? If you want, make a zip of your blender or fbx file + textures I'll look at it when I'm home
It looks like you've got an AO texture on there that doesn't match up to the model as well, so it's a little difficult to tell what's goin on with the lower arm. I do see some objects with inverted normals, though. In edit mode select those parts and press Shift+N to recalculate normals. It should flip them back to the correct orientation; if it doesn't you may need to check the "inside" (or similar) box in the lower left tool palette that pops up when you press Shift+N
