National Differential has been remanufacturing differentials for decades. Along with transfer cases, remanufactured differentials are our bread and butter. Our customers come to us for a variety of reasons; some need to repair a damaged differential, some want to upgrade to a better one, and others are building their own custom rig and need a differential capable of the most extreme pressure. No matter what brings them to us, they all come for the same reasons: the guarantee of top quality work.