I am a mechanical engineering graduate who wants to work as a CAD engineer. Is there anybody on here who can fill me in on what to expect? I am certified with inventor, used it for over 5 years but have not touched autocad. I dont know much about drafting in terms of part and assembly drawings in real life projects, and im not really sure on what to expect from a CAD engineering job based in mechanical projects. Is there anybody who could give me some insight into aspects of the job as a CAD engineer, and how a project starts and finishes in terms of part, assembly drawings and use of software etc? Thanks for any replies. 

No such thing as a cad engineer.  There are cad techs and cad managers however.  There are also engineers who use cad as a tool much as they would use a calculator or a spreadsheet.

Large well established companies are moving away from using generic AutoCAD towards such programs as Revit.  Revit is considered to be a "modern" cad program and is nothing like AutoCAD.  I suggest you look into Revit MEP.  Start with this link...

http://www.autodesk.com/products/revit-family/overview

I fail to see what vital information that ^ ^ ^ post imparted to the OP.  How does learning shortcut keys benefit someone doing mechanical design using CAD?  What do shortcut keys have to do with parts and assembly drawings?

I'm sure he could teach us a trick or two about shortcut keys.