Originally Posted By: Thugzy
Yes its specified as lifetime, but my MB tech says to change it out at 60k-Kms as there have seen failures on high mileage GLK/C-class...belief is earlier fluid change should reduce failures.
Thanks for the inputs...
Mercedes no longer specifies any automatic transmission fluid as lifetime. This was a running change back in 2010 or so, and was retroactive to previous model years. They now recommend doing the first change at 60,000 km, and then doing every other change at 120,000 km intervals.
HOWEVER, the Benz recommendations for the late model "rest-of-world" vehicles (i.e. outside North America) is EVERY 60,000 km for tranny fluid. So I would simply follow that recommendation and do a transmission fluid change every 60,000 km. This includes draining the torque converter in addition to dropping the pan to get all of the captive fluid out. If you do, I doubt you will have any issues later (fluid related ones anyway).
The best fluid to use is an approved 236.15 fluid as your transmission is likely a 7G-Tronic Plus, which uses the blue "FE" fluid (not the 236.14 red fluid). The OEM fluid is Fuchs TITAN ATF 7134 FE. You also must buy a new pan gasket, new pan bolts (as they are one time use), new filter, new drain plug gasket, new drain plug stand pipe (to set the fill level), and new torque converter drain plug and gasket.
The transmission is filled through the drain plug. In a nutshell, it is initially over-filled, the vehicle is idled until a specified transmission fluid temperature is reached (45 C I believe for the normal 7G transmissions, but I don't know if that has changed for the 7G Plus ones). Once the fluid temperature is reached, the fill apparatus is removed, and the excess fluid is drained out until it is no longer a "steady stream" (with the vehicle continuing to idle for the entire time). At that point, you're done, and you replace the drain plug and call it a day.
For the front and rear diffs, Benz uses a special VII-free 75W85 synthetic GL-5 fluid for your model year. They specify it that way so that it can last a "lifetime". However, I wouldn't hesitate to replace it with any high quality synthetic fluid if you're willing to continue to change them semi-regularly.
Transfer case should be part of the transmission sump on your model, and thus does not require any separate draining/filling procedure. You may want to have your tech double check that though, as I'm more familiar with the previous gen 7G transmission.