A method of monitoring and controlling a transmission in a marine propulsion device comprises the steps of receiving a rotational input speed of an input shaft to the transmission, receiving a rotational output speed of an output shaft from the transmission, receiving a shift actuator position value, and receiving an engine torque value. The method further comprises calculating a speed differential based on the input speed and the output speed, and generating a slip profile based on a range of speed differentials, engine torque values, and shift actuator position values.