gearbox plugs

Can anyone help!

both the drainage and refill plugs are seized solid on my gearbox and I lost some fluid when cleaning the box so need to top it up. There is a small plug on the top back of the gearbox behind the breather (between the rear stabilise) can this be used to top up?

Hi they may seem seised but mine were fing tight as hell so just try undoing em I had an extension on an extension when undoing mine

people go silly tight on these, best adding bit of ptfe tape on them as a:it stops leaks & means don't need do um up silly tight b:reduces corrosion issues between alloy & steel .
You could try adding a little oil via breather just keep you running but ideally those plugs need come out even if needs old modded extension welded in them. First off try a proper drain socket tool in nice cleaned out plug .
Pain in the ass them them plugs at times :-/

By the looks of things someone has used something to seal them in and they are solid. Was using a breaker bar and drain plug tool but no joy, so for time being I used the plug on top to top it up with 1/2ltr

maybe some heat will help soften any bond on threads.