My assumptions were right. I went to my Amsoil Rep today and I picked up an SDF-80 Donaldson Endurance Oil Filter. It was made in Mexico. My Amsoil rep was shocked (He has a lot of American Flags hanging up in his store). I told him I hope Amsoil does not sell out on their regular filters. So I will be buying Fleetguard for my Heavy Duty applications. It is pretty interesting because these Endurance Filters by Donaldson are not cheap. mikeyoilnutt