Picked up front and rear diffs for a grand total of $350 from an awesome junkyard in Charlottesville called Harry Wrights

Question - front diff is ADD, but my truck is manual hubs. I read the tech article about defeating ADD and realize that that is probably the path of least resistance. However, I would prefer to actually implement the ADD. Anybody ever took a manual hub truck and make it ADD? I am thinking that I would simply lock the front hubs and then I would have to run some sort of vacuum to the diff and control through a switch somehow... just that simple, right <img src="/forums/images/graemlins/lol.gif" alt="" /> ?

Thanks much!