I decided to change the gearbox oil and was surprised that only just over 1litre was drained off. This was after driving the car to heat the fluid and jacked up at the passenger side to extract as much as possible. I know the capacity is 1.75l, and didn't expect to drain off this amount, but just over 1litre was surprisingly low. However when I topped it up on level ground just over 1l was all that it would fill to before the excess dripped out.

Does anyone who carried out this op. remember how much they drained off or have a similar encounter?

Is there something else I should be doing?