Changing the plunger washers on a remote gearbox

[Carpeta]

Some oil is leaking out of my remote gearbox in a few places. I wanted to change the copper washers on the oil drain plug and the two plungers on the back of my installed gearbox.

I linked a video from Cole's YT channel "Classic Mini DIY" where he screws in the two plunger:
https://youtu.be/ve5HbSbrdj8?t=877

Can a gear be engaged or would it be better if the gearbox is in neutral? Does that make a difference?
Do I need to pay attention to anything else when removing and installing?
The oil is drained off first, of course!

[Spider]

It doesn't matter if it's in gear or neutral to change the Plunger Washers, just be aware there is a Spring in there and while not huge forces are there, it will cause the cap to be under some pressure as you do that last thread.

[Carpeta]

Thank you very much Spider!
I'll make sure the spring doesn't fly into my eye or anywhere else when I loosen the screw.

[Peter Laidler]

New copper washers..... I always anneal* them before I use them. And in any case, a bit oof sealant never goes amiss I say. Others might disagree.
*Deep cherry red and quench

[Carpeta]

Thanks for the tips Peter!
I bought a large assortment of copper washers in various sizes some time ago. There should also be suitable ones for the oil drain plug and the two plungers. ^^

[Spider]

New copper washers..... I always anneal* them before I use them. And in any case, a bit oof sealant never goes amiss I say. Others might disagree.
*Deep cherry red and quench

Yes, totally agree with Pete here.

Just be sure to really get the thread in the case and the plug super clean before applying the sealant, really really super-duper clean.

[Carpeta]

Job is done, thanks guys! Hope the gearbox stays dry!