I do not believe that Ayas checked the entire mechanical part, if it were so, the problem was already discovered, the truth that this type of failure is difficult to save them when you do not have the vehicle to observe well and personally slam the noise, if it is dry as a blow it may be that the problem comes through the butterflies of the 4x4, you can have crooked or misaligned, or not tightly firm They normally fail and some of the supports, then the rest, could check the oil from the box and be to be that it does not have metallic particles, since you can have a wear of the components.