Gearbox and rear diff oil - looking for recommendations and quantities?

6 speed manual 132kw 2011 4Motion

What are people using and is there anywhere online to direct me to the quantities for both gearbox and rear diff? AKA a service schedule?
Also the frequency they should have been changed because there’s not much in my service manual and I have a slight leak from the drain plug on the box so need a new crush washer. I’d like to have it before I dump the oil at the next service at 180,00kms.
And also service the rear electronic diff lock diff if that makes sense. I’ve seen it done online before but can’t remember where?

TIA Markee