Yes I have read with interest, all about these sealed for life transmissions.
My understanding is that on the ML320, you cannot drain the torque converter. However there must be a way of draining, who would only drain some of the oil, out.
I presume there is a special dipstick for checking the oil, also can you buy the seals, to seal it up when you have finished.
As we intend to tow a trailer a lot, we would be changing the transmission fluid every 30,000 miles.
Any one throw any more light on this subject.
Col Tigwell Downunder