I thought every Mercedes transmission up until September, 1999 had a torque converter drain plug. I just serviced my transmission a week or so ago and it took me awhile to find the drain plug. The torque converter turns a lot more than I expected with just a little bit of movement of the crankshaft. If I wasn't certain that one was there, I might have given up on it. Got about 7.5 liters out by draining both drain plugs.

Len
'99 E300TD 100,000 miles