In civil3d try turning proxygraphics to a 1 in the command line then save.
You should see the file size get absolutely huge. That will be autocad
storing all the contours as polylines instead of calculating them from the
surface stored in the file.
If that doesn't work it is likely that the surface is a reference. If that
is the case in the command line open the properties box by typing mo,
select the contours/surface and run explode in the command line. Select
again and it should be a block in the properties window. Explode until you
select a polyline. Save and open in arc map.
The other issue you might be having is civil/survey guys love to work in
meaningless coordinate systems when it comes to GIS. If that is the case
you will want to get with the project surveyor to get scale and rotation
information.
Hope this helps.