Abstract: The external heat transfer loop of a slide ring/counter ring type seal is eliminated by provision in the seal structure of a mounting subassembly which comprises a fixed housing block, of one-piece or multi-piece form, holding the counter ring is axially fixed position and having circumferential and end face extended surfaces, such as ribs, for heat dissipation to ambient air. The mounting block has smooth surfaces in metallic contact with corresponding smooth surfaces on a back face and on a peripheral face of the counter ring with at least one-third of the total surface area of the counter ring being so contacted. The counter ring has a front step overlapped by a gasket and holding a collar extension of the mounting block.