Yes I took it to a mechanic here in Spain, and he look the oil, and it was good, I changed the oil when i put the sti v3 gearbox... Yeah, might be, this "cla cla cla cla...." does it usually uphill... and when I do a downshift it does weird noises coming from the back, but doesnt sound like the rear differential itself, sounds more to the exteriors of the car... I guess its the bearings because the suspension doesnt change when I shift gears...
Also I heard a noise like the machine that the butchers use when cutting meat.. but that might be the brakes i guess :P