Daniel,
Sounds like you are using the AutoCAD geolocate option rather than the Esri coordinate system definition. The AutoCAD version of defining a coordinate system can be like warping the world to your drawing, where as the Esri coordinate system assumes your drawings coordinates are drawn in a world coordinate system. Even if they are you have to identify what that coordinate system is. Sometimes they agree. You may just have to use the ArcGIS for AutoCAD assign coordinate system tool on ribbon. ArcGIS for AutoCAD only recognizes the Esri coordinate system defined in your drawing. If you fail to specify a coordinate system then it the first service you connect to will define the coordinate system. If that first service is a ArcGIS online base map like the world imagery then your drawing will think it is in web mercator, which it probably isn't. If that is the case you'll want to remove the esri coordinate system and assign the correct one for your data. There are thousands of nominal coordinate system to choose from that ship with ArcGIS for AutoCAD. You could also define a custom one using the syntax of a standard Esri .PRJ file.
