Brett is correct in that it should be a 2 alpha code. As far as location, it is stamped on the axle housing on the drivers side. It is on the rear side of the axle housing mid way between the brake backing and the gear cluster. It can be difficult to find. The letters are pretty small and can be covered in years of dirt and grime. A wire wheel can help scrap off crud in order to find it. I've also found some to be "hidden" beneath the brake line.
