Your ird holds 1.1l of 75w90 specification API GL5
rear diff takes 0.83l of80w90 api GL5.
Don't know what engine you've got gearbox oil differs,all the info is written in the haynes bible,but it states 10w 40 for the manual gearbox ,I rang the dealers,spoke to a mechanic there,he reckoned it should be 75w80/75w90 semi synth.
I dont know what you mean by the crown wheel?
It takes perseverance to remove that filler nut,if youve already rounded it heat an 18mm socket till its nearly red hot,get a 9" extension onto it quick as you can and tap it onto the nut,order a new one first,you'll also need a 21mm copper washer.
I messed up my filler nut so bad I had to use a red hot 17mm socket to get a hold on it.I hope this crap I've typed helps you out somehow.
Be careful using those axle stands,I was in my parents house last week,saw a lidle leaflet pair of axle stands for a tenner.My mother who is a nurse told me horror stories of guys who came into a&e,because of axle stands folding.Also was going to buy some years ago from a trusted auto factor,the guy told me id be much better off with concrete blocks and wood.