Picked up some interesting info re BMW from parts dealer fcpeuro, which IMHO fits Merc to the tee and is called:
"Why BMW's "Lifetime" Automatic Transmission Fill Doesn't Actually Mean "Lifetime"
My 2007 C220 CDI W204 did not get its fuel filter changed nor its auto. trans. oil/filter changed at the recommended 60,000km (40,000 miles) and also not at 120,000km after which I bought the vehicle second hand. Excuses by service managers here in Perth, Western Australia: "The customer did not wish that service done!"??. So a customer brings his car for service and is then asked, do you really want a complete and recommended service?
Needless to say, the trans oil stank when I did the oil change and the fuel filter showed signs of contamination after I cut it open. Admittedly, without a flushing machine and knowledge it is a tricky process as oil stays behind in the torque converter and you can only ever get 3.5 litres out of the total of 7.5 litres, so it becomes a repeated remove/fill flushing process and the oil is quite expensive. The Merc trans oil pamphlet also talks of "Filled for life"?
The attitude by BMW is the same as for Merc: We give it a life of 100,000 miles or 170,000km and then the warranty/good will has expired and you better buy a new car! There is even the suggestion from a forum to never change the oil as the rubbish in the oil will ensure more friction and grip and changing the oil may lead to slipping during gear changes?
After oil pan removal, cleaning and gasket/filter change, the oil can be repeatedly flushed by hand-pumping or 12V electric $25 pump via the dip stick tube and level can be checked via $20 dip stick ex Hong Kong; Merc wants AUS$80 for it!. The recommended 80 degrees during filling can be checked via an infra-red thermometer.
Let's hear your comments!