I have an aluminum case Warford for my TT and am trying to learn more about it but can't find any just like mine. All of the ones that I see pictures of are made in New York by the Warford Company. Mine has Warford embossed in the side but is made by the Warren Gear Corp. in Warren, PA. It has the over, direct and underdrive. Does anyone have one made in Warren and is it the same as the ones made in New York? Are parts interchangeable?