loud dif on a 97 liberty

[SirGoat]

Hey my flat mates car is making to me what sounds like wheel bearing but his mechanic is saying is the dif, its like a howling or throbbing sound. Apparently when the mechanic change the oil it was metal shaving tastic so i am inclined to believe he could be correct.

1. is there a recommended miracle brand of dif oil that might shut it up?
2. What would a second hand lower km dif be worth?
3. The mechanic says its harmless at the moment aside from the horrid noise?

the car hasnt really towed very much, its lowered and inst driven softly but being a NA 4 banger he doesnt take it to the track or anything. Has ~180k on the clock and would say the previous owner was similar in as much as he got it with rice cannon, tints, lowered, rims, overly blue headlight bulbs to give you an idea ...

any help would be great he is overseas for 5 weeks so no rush.

[RB30-POWER]

front or back diff?

fairly sure all the s/hand car dealers used bannana peels back in the day.

all you can try is like an 85-140w (truck) gear oil and throw in some nulon g70 at the same time.

if it like my car it will do two tenths of bugger all.

in the past, i drained a vt commodore diff, put in fresh oil with gmh additive), was real loud, so obviously had something in it( suspected it as it was real thick hardly ran out), so drained the new oil, filled the diff with donalds 3 in 1 oil additive, was a real mission to get the stuff in as it so thick, once i got it all in, it was around 80% as quiet as it was orignally, whatever it had in it was good, i suspect possible bannana peels.

week later owner decides to throw a new diff in it anyway, fark! after getting all that donalds in there, haha!

so fact is sometimes you can quiten them down, othertimes you can not.

as long as its got oil, its unlikely to suffer catastrophic failure, but if you were planning a trip across the nulibor, would you risk it.

[JZK25]

I would be getting a second opinion, wheel bearings are uber common failures on liberty's, diff's not very. To check for sure you need to pull the brakes off and driveshaft out. It will be very apparent that the bearing is buggered just by turning it by hand then.
i can tell just by rotating the wheel by hand but I have seen millions of them so am prolly a bit more tuned to it than your average bloke.