# How to separate mixed signals, 3 identical gears meshing together

I have 3 identical gears that are meshing together, on each shaft that is holding these gears I have an accelerometer recording vibration data. Once I move to the frequency domain via MATLAB's fft I am unable to see any specific frequency that would describe the meshing frequency of my gears, it looks all the same.

Are there any methods I should be looking at to tackle such a challenge of identifying the gear meshing frequency and probably identify which gear is inducing what frequencies?

Also would it make any sense to run the motor while disconnecting the gears and record the vibration induced by the motor, and analyze that to filter out the motor's influence?