Regatta - how much gearbox oil?

In all available sources (Haynes, Fiat Regatta manual/instruction, oil companies web pages) the amount of gearbox oil is slightly over 3 liters in the Regatta 5 gear box. However, following the instructions of draining the oil and then filling up until oil falls out (red arrow), I can't get the gearbox to accept anymore than ~1.5 liters.
Despite the age and miles (238000 km), the gearbox works quite well, but with a noise that could indicate too low oil level.
Does anyone know if the correct amount is ~3 liters, and if so, how do I fill it up?

Thank you in advance.

Hi mate.

Did the full 3 litres come out when you initially drained the box?

Cheers,
Alan

No, out came approximately the same amount as went in = 1.5 liters. But that can mean that the previous owner did the same mistake as I'm doing. I find it strange if all volume numbers printed on paper are wrong.

Hmm, yea i see what you mean. If its on level ground, then all you can really do is fill it untill it comes out of the filler hole, as it is impossible to get any more that that in. Ive had a look through some manuals, but couldnt find a specific amount.

I'll check with the company that took care of the service previously, but if they don't know, I think I'll leave it for now.
Thanks for your help.

/ Mathias

looks like the plug is a filler/level plug,and as such the correct level is when it dribbles out the side.dont pay too much attention to capacties,that was for a dry engine when the car was new,and doesnt take into account all the sludge etc in the bottom!i once filled up a Reliant engine not by using the dipstick,but by putting in what it said in the manual,the oil level was halfway up the entire stick!i then had to drain it out.hope you can work out what im trying to put across lol

I agree with you on that, Dan. I have decided to stop worrying about this, and spend my time and money on other minor issues with the car.
If I find something out, I'll post it here.