Welding advise

Hi all, I have a slight weep on the tube casing of my 90's rear axle, just on the manf weld near the shock mount, got to get the welder out soon (mig) so thought I might seal it up.

Questions, do I need to drain the oil out first? should I just take out the filler to allow it to "breathe"? do I just do it and change the oil afterwards, or just do it and leave the oil anyway as it was changed 6 months ago.

You might have guessed by now that for this job I really don't have a clue. Don't want to turn the back axle into a bomb while I'm under it.

Cheers

not an hexpert but would say draining is the best option

the question is why is it leaking? has the case gone thin? has it rotted away or is it damaged? you might need to replace the axle tube