Chanced upon a good article and would like to share.
While driving, if some whining noises is heard, here's how to diagnose them
If the car is in Park or Neutral, and the whining noise is still present, gearbox needs to be checked
If the car is moving and whining noise only occurs when accelerator pedal is stepped [ whining may be more pronounced especially above certain speeds eg >60km/h] and goes away when feet is off the accelerator, the rear differential needs to be checked
If whining is constant throughout the drive and the sound is more pronounced when swerving left and right, the front wheel bearings need to be checked.
If car is in Park or Neutral with ignition switched off and the whining ensues, you probably have to find out soon what the children or missus needs.