http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1Z515Q6881Z70RZ511&year=1992&make=MB&model=600-SEL-001&category=All&part=AT+Filter+Kit
There is the filter kit for your car.
MB trans are cake to drain the fluid on. Drain the pan, drop it. Rotate the engine till you can drain the TC, drain that. In the owners manual it tells you how much fluid it holds. Put it all together fill it up run it and check it.
If you can do it on a Chevy you can do one of these, its much simpler to do and these cars are built 10 times better so they include nice things. Like drain plugs in the pan, and the pan bolts bottom out so you cannot over tighten them.