Oh sorry, I think you asked me about this before.
The transfer box and the rear diff is done every second service or intervals of 20k miles. There is no requirement to change the oil in the box, one of these sealed for life jobbies. However, I will do mine about every 4th year. Use only the proper 75 grade oil and sit down before paying for it.
I always take off the undershield to do the transmission oil.
Take the plug out of the transfer box and let it drain (green circle). Don't bother with the level plug, there is a filler plug high up (blue arrow) which is easier to get at;
0.45 litres of GL5 80W/90
You might find one of these useful;
OK, if you do choose to change the gearbox oil you need to remove the drain plug;
Then the filler plug;
But don't try to fill it through the front unless you have the above pump as you can't tip normal oil bottles up. Instead, take off the small access panel under the wing (2 clips) and fill from under there. It only takes 2.1 litres;
OK now round the back of the vehicle and take out the drain plug (green circle - passenger side). Because of the internal clutch this will come out filthy;
Now round to the drivers side and take out the level plug (blue circle). Fill with 0.55 litres of GL5 80W/90 and you will see why one of those pumps is a good investment - it is very awkward with an oil bottle!;
PLEASE NOTE:- 2009 on models should use SX API GL5 85W/90 for the transfer box and diff' according to the data sheets. The only place I've managed to find this is from Toyota themselves.