Yep it takes 2.2 litres but can take up to 2.5 litres safely. 1 litre means either you have a leak or you haven't taken it all out properly. Are you sure you are draining it from the drain bolt? it's located at the front as if you are looking at the box face on from the front of the car, and is on the lower section of the bell housing.
It will be a hex bolt ..