A fluid transmission fitting (100) includes a female coupler (47) inserted within a hydraulic feeding block (1), and a male coupler (48), which can be coupled to the female coupler (47). The hydraulic feeding block (1) includes at least one hydraulic line (49) and a draining line (50), and a lever (4) integral with a cam (7) adapted to relieve the pressure from a chamber (54) inside the female coupler (47) and adapted to uncouple the male coupler (48) from the female coupler (47). The female coupler (47) including a pressure relief valve (51), which puts the chamber (54) into connection with the draining line (50).