I just replaced mine when I changed the engine and clutch, it took 3L fully synth manual transmission oil; I got mine from fiat 29 quid, it was a bit expensive you proberly can get it cheaper elsewhere, it was just easy as I was there getting a gearbox seal. Tip make sure the inner CV boots are secure and not leaking, as these are the only things holding the oil in. The filler plug is opposite the charcole filter and is a little awkward to fill, I used a long flex funnel. Keep filling until it dribbles back out of the hole. I aslo used a large tork socket to remove the plug. If you want to drain the old oil out the plug is located lower right of the box.