Though I really need the full part so I can run the simulation. Do you have any idea as to why the mesh won't work with the full model?
I don't know why, but check whether any part of the geometry is different between the half I kept and the half I rejected.
If your loads are symmetrical, you should run the simulation on half the model using symmetry. Even if it’s all just close to symmetric, I usually do so and keep the worst case half.
Some general ways to get the model to mesh:
Use a finer mesh
Do geometry check and geometry analysis to find goofy areas. Anything these turn up will often cause mesh problems. You can eliminate them or try to use mesh controls.
Increase the mesh tolerance (in standard mesh) to ignore small features.
Here are some areas I think might be trouble. Using standard mesh and automatic transition should get the mesher over the hump on these. I didn't do so because I thought the mesh size would get out of hand given the large number of small features. Instead of automatic transition, you could try mesh controls in these areas.
Why do you need he full model?
But like mike says, interrogate the model to see what is different.