How to change the gearbox oil ?

[Pich]

Can anyone tell me what type of gearbox oil the 172 has and how much ?
Also can anyone tell me how to do it ? Please

 

[bmh.01]

75w80, 3.5l iirc.

Wants a new copper crush washer from renault for the drain plug, otherwise its a simple case of dropping the old stuff out the drain plug on the bottom and filling it up until it comes back out the fill/level plug.