I wonder if you have figured out a solution yet. Someone replied regarding xref issues, that may have been the issue, I don't know. Another possibility is that the data you want to see is in some format which will not convey directly.
I have been using Autocad map 3d 2014 to export shapefiles which I can use in ArcGIS. You can do that too, you can get a free trial version for a month. I am lucky to have a lot of years experience using Autcad though, dont know if you have that experience.
I found that I had to also download an object enabler from Autodesk to see some of the AECC objects in Autocad Map, the water line alignments I needed.
Even then, once I could see the AECC objects in Autocad Map, I found that I had to explode them before I could export them as shapefiles, and then I lost information I would have liked to save...such as station numbers and more.
I am still trying to figure out the best way to export the lines and attributes the way I want to. I am looking at an Autodesk Civil 3d free trial now, to see what export options I get there. It looks like I can export AECC objects, but Civil 3d doesn't provide the tool to export a shapefile..so it's back to Autocad Map for that part of the process.
One of these days I hope I can figure out the best way to do all these things, and perhaps without having to buy so many expensive softwares to do so few functions.
I may have said a lot of things you find unhelpful, but I do know some things about Autocad dwgs, and I am trying to do something similar, so perhaps I can help. For me what is difficult is not knowing much about Civil 3d, but I hope to learn more in the next month.
