A method for monitoring a gear and bearing system having at least two inter-meshing gears and at least one bearing includes detecting gear and bearing vibrations with at least one vibration sensor operable to generate a signal representative of the detected gear vibrations. A carrier frequency is identified from the generated signal. A band pass filter is applied to the signal at the carrier frequency to create a filtered signal. An envelope is extracted from the filtered signal to create an extracted signal. A time-frequency analysis is then applied to the extracted signal which allows for identification of degradation of the gears.