The invention relates to an optimization method for optimizing the thermal engine speed (30) of an automatic gearbox (32) type vehicle during a transfer, for implementing an optimization device (1) in communication with an engine control module (2) and a
clutch control module (5), said method comprising a step in which real-time engine speed information (RMTH) is provided by the engine control module (2) to the optimization device (1), another step in which the real-time engine speed information (RMTH) is compared by the optimization device (1) with engine speed
setpoint information (CRM), and yet another step in which, in the event of a mismatch between real-time engine speed (RMTH) information and engine speed
setpoint (CRM) information, the optimization device (1) transmits a fade factor (FG) to the
clutch control module (5) for
fading the
clutch torque gradient to limit the clutch torque gradient.