I have read your postings on lew rockwell. My car, according
to the dealer, does not require a change in transmission fluid.
However, it is my understanding that a transmission flush with
a fluid change will greatly increase the life of the transmission.
My car has no fluid dip stick or means to add fluid. What can
I’ve read that Mercedes (and BMW) no longer provide physical dipsticks to check oil (the level is checked by computer, electronically) and that to drain the crankcase, the oil must be sucked out rather than drained. Perhaps this is the same as regards the transmission.
I, too, would be nervous about so-called “filled for life” or “service free” transmission fluid (and filter). Especially given the stratospheric cost of replacing/rebuilding a Mercedes transmission. I’d also want to changeout the fluid and replace the filter at least once every 30,000 miles. But, to do so, you’ll need two things: A way to drain the transmission and then a way to re-fill it when you’re done draining it.
The first should be easy enough, provided the transmission has a straightforward pan that’s bolted to the case. This can be removed and then a generic drain fitting added. Very simple.
However, you’d then need a way to re-fill the transmission. If Mercedes does not provide a filler tube/dipstick, the only way I can see this being feasible is via the cooler lines or some such – and a professional flushing machine.
This may be the best route. Any fully-equipped transmission shop will have the necessary equipment. Look for one that specializes in German (or European) cars.
Hope this helps!