which oil for 6 speed box

[analog_me]

Hi all,

I would like to change the oil of my 6speed box, do you know what to go for?
I remember having read several time the best one is the standard one for reduced noise and feel but which one is this?
also is there a point in getting a slightly more viscous for a tired box?
Thanks

[analog_me]

Thank you,
As per my internet search the filling point is on the side and needs to be filled in until it starts to overflow but how much is this in liters?
Furthermore is there a bottom drain on the box to remove the old oil ?

[analog_me]

As I was looking into how to best replace the grearbox oil I discovered since the last two years and 8000 miles I own the car a plug is missing from the gear box driver side above and behind the speedometer pickup point, close to the gear lever. Do you know that this is?
It is in the place the red plug is located in the caterham website showing the 6speed gearbox.
https://caterhamparts.co.uk/gearboxes/5204-gearbox...

Edited by analog_me on Thursday 11th October 21:17

[analog_me]

My old mechanical speedo is where the yellow plug of the picture is, further forward and lower down.