There's just enough room to get a stock funnel into the gearbox with panels on. My Type 9 took about 1.9 litres:
The Sierra 3.62 ratio diff took about 1 litre. Its also managing to leak/weap very slightly from one of the back plate bolts, so off to Machine Mart to pickup a T45 Torx bit to give it a tweak. I'm assuming/hoping it was the one loosened to original drain the oil (before it was in my ownership):
Not much to see...
Update +3 hours: I couldn't move the cover bolt in question & its not leaking anymore... I think I'll just keep an eye on it
Update +24 hours: no leak... perhaps the original was a splash from filling?
Update +5 days: no leak... result! it must have been a splash/drip from filling