Hi mate,
Gear box- about 4 litres, 80-90w gear oil
Front Differential (axle) - about 5 litres, 80-90w gear oil
Rear Differential (axle) - about 2.5 litres, 90-120w LSD oil. You need to check whether you have an LSD or not, my GQ does. If not LSD then 80-90w oil should be fine.
I would do the transfer case too while youre at it, another 2 litres or so of 80-90w oil.
In Australia the best brand is probably Penrite, but its expensive. Castrol etc. are all fine, just use what your budget allows.
Make sure the filler plug opens before you drop the oil, otherwise youre gonna be in a world of pain, Good luck
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