87 tx3 turbo 4wd gearbox oil

[ayeayre]

servicing my 87 tx3 turbo 4wd
just wanted to know how many liters do i have to put in the gear box and what size is the drain nut?
the entry is underneath that small black box (something to do with air intake i think) which is underneath the dizzy, yeah?

also can someone please give me info (or link) on changing oil for transfer case and diff?

thanks a lot