[W126 Coupe] leak from automatic transmission

[Kent Kihl]

Hi
I got a leak from the gearbox, the last few months there has some noise, and
last week I discovered that the fluid in the gearbox was so low it didn't
even show on the stick. I have since then put in 4 x 500ml, and it is empty
again, have only driven about 250 km. 
I have not had a look underneath yet, is it something I could change or does
it has to be at a workshop. The car has 8 km left to 200.000 km.

Kent
Cape Town