In the literature reports on the vibration based localized faults detection of epicyclic gear sets, the vibration sensor is often mounted on the ring gear or the housing adjacent to the ring gear, which ensures the vibration transfer path between the mesh point of the ring-plant gear pairs and the sensor is the shortest when the planet gear is under passing the sensor and the corresponding vibration has the highest signal-noise ratio (SNR). However, this sensor mounting position is often too ideal to be utilized in applications. For example, three types of structures of epicyclical gear sets commonly used are shown in Fig.1. It is noted that the ring gears can be rotated in Fig. 1 (b) and (c), which are challenge for selecting a suitable sensor mounting position. As well-known that the bearing housing utilized as the sensor mounting position for a fixed-axis gearbox is widely adopted in applications. However, the bearing housing sensor mounting for the vibration analysis of epicyclic gear sets is still an issue. It has two drawbacks for the vibration picking. Firstly, the vibration transfer path is much longer than that of the sensor mounted on the ring gear. Secondly, the noise from adjacent bearings can lead into the picked vibration. Then, the bearing housing sensor mounting is few reported in the literature. On the other hand, the bearing housing sensor mounting can be implemented in most applications of epicyclic gear sets. Then, it is worth investigating whether the bearing housing sensor mounting can be employed for the localized faults detection of epicyclic gear sets. To address this issue, an experimental investigation has been carried out on a planetary gearbox test rig for the vibration based tooth-root crack faults detection. Experimental results show that the fault feature contained in the observed vibration from bearing housing is weaker than that obtained from ring gear position. However, the bearing housing sensor mounting can also be utilized for the vibration based tooth faults detection by using the well-known vibration separation and the synchronous average techniques. The spectra of the vibrations picked up at the two mounting positions are shown in Fig.2, where the characteristic order (3.55X) and its harmonics related to the tooth-root crack of a planet gear order are exposed clearly.