transmission shaft(n = noun.artifact) - rotating shaft that transmits rotary motion from the engine to the differential;
is a kind of rotating shaft, shaft
is a part of gear box, gear case, gearbox

air shaft, airborne transmission, automatic transmission, butt shaft, direct transmission, elevator shaft, fiber-optic transmission system, fibre-optic transmission system, hydraulic transmission, hydraulic transmission system, indirect transmission, lay shaft, rock shaft, rotating shaft, rotor shaft, shaft, shaft louse, shaft of light, standard transmission, transmission, transmission channel, transmission control protocol, transmission control protocol/internet protocol, transmission dynamometer, transmission line, transmission mechanism, transmission system, transmission time, vector-borne transmission, vehicle-borne transmission, ventilation shaft, way shaft