On the 2.3 van with the MLGU box it's easiest to just unclip the breather cap from the top of the gearbox and refill through a funnel attached to a length of tubing. Removing the air filter box cover and the air filter helps with access, but isn't essential.
You do need to fully drain the box first and replace with the correct quantity of oil, as there's no facility for checking the level.
That's the method used in the Fiat manual.
Hi from Australia. Can you please help me. I attach two photos that I need help with. I have the 180 multijet 6 speed. Can you tell me if in the photo that is the filler plug and in the second can you please tell me what the white bottle container is for. Kindest Regards MervThe 3.0 has a different gearbox to the 2.3 with different fill location, no benefit in removing battery box, but filling can be done without removing air filter using tube and funnel as per my previous post.