Hi Guys, I've got an '06 Jimny with 19k on the clock and on smooth roads under mild acceleration I have noticed a quiet 'wah wah wah' noise at around 45-55 mph. I checked the front diff and the oil was clear and up to level, the center 'Diff' was low on oil but no leaks and clear oil so I topped it up, however the rear diff was up to level but the oil was very black and when the drain plug was removed the magnet was covered in black metallic sludge, I put fresh oil ( LS 90w ) in but the noise is still there. Can anyone please tell me if this is normal and the noise/crap in the rear diff at such a low mileage is usual with these vehicles. The car is currently in France with a 'non techi' driver so I'm concerned somthing is going wrong, thanks in advance to anyone who can advise me. Gary.