Manual gearbox oil change

[ZedsDeadbabyZedzdead]

Good evening

I’m going to ask my mechanic to change my gear box oil despite him saying it doesn’t need changing as it’s “lifetime oil” and I understand it needs GL4 75w 80 however I’m unsure of how much I need, does anyone know how many litres are required please?
The reason I ask is that I plan to take the oil with me so have to buy it tomorrow.
Thanks

 

[Crawford08]

Which transmission do you have? There are 3 different possibilities but I think they're all between 1 and 2 quarts

 

[colb]

It takes a touch over 2 litres so buy two bottles, you will have about 3/4 left over, once drained it is filled till it overflows from the fill hole.
Fill for life really means the life of the BMW Warranty from when it was sold new, surprised your Mechanic thinks its not required because of that. Once changed it will make a noticable change to the gear selection making it a lot slicker and smooth.

 

[ZedsDeadbabyZedzdead]

Thanks for the help