Abstract: Dispersion of eutectic material (56) in a thermal disconnect coupling following thermal actuation is avoided by disposing the body (56) of eutectic material in a first axially opening cavity (40) in a driven shaft (24) having teeth (32) normally meshed with teeth (22) on a driving shaft (16). The first cavity (40) is closed by a wall (50) forming part of an output shaft (26) and the interface of the cavity (40) and the wall (50) is provided with seals (92, 94). The first cavity (40) is separated from a second cavity (42) in the driven shaft (24) by a perforated web (44, 46) and together with an element (60) supported by the output shaft (26) defines second chamber into which the body (56) may flow upon thermal actuation. The interface of the element (60) and the second cavity (42) is provided with seals (92, 94) to prevent the escape of eutectic material from the second chamber.