UPDATE: since the time i made this video i now have better understanding of the thermostat that is included in the additional-cooler, the fluid will always bypass the thermostat regardless of the ATF temperature, if it is lower than 90 it will pass through the rear openings and the whole additional cooler is excluded from the circuit, And if it is higher than 90 it will open toward the front and allow the ATF to pass through the cooler.
SUMMERY: regardless if your car is equipped with Additional cooler or not, when flushing just proceed like it is not equipped and follow the steps from the video.

If you planning to keep your Mercedes Benz for long time, here is one service that you must do, unlike MB claims that the newer transmissions are filled with life time fluid and they should not be replaced, my experience tells me it’s a matter of time before your transmission fails if you don’t execute frequent fluid changes or better fluid flush (not the scam 10 min service center fluid flush, rather a professional fluid flush as described in this video).
The procedure take less than 2 hours and mostly standard tools, any extra tools and all parts are mentioned here.
I recommend fluid flush every 40K mile or 60K km.

Required parts:
BLUE MB ATF 10 Liters, spec number 236.15, ATF 134 FE, 0019897703
ATF filter 2222772000
Pan gasket 2202710380
Green overflow pipe 2222710097
6 new pan bolts (recommended) 0049903512
Drain plug washer 007603012102
ATF return line o-rings (2) 0199975845

Special Equipment
722.9 filling adapter, I used MVA588 adapter
Fluid pump, I used MOTIVE POWER FILL PRO (2 GALLONS)
½ INCH INNER DIAMTER LONG CLEAR HOSE
A quick disconnect coupling

722.9 generations differences:
Non-chamfered pan (black overflow pipe), Uses old red fluid spec (236.14), temperature for fluid adjustment is 35C/96F. Mercedes recommend replacing this pan with the newer chamfered pan with the white overflow pipe.
Chamfered pan (white overflow pipe), Uses old red fluid spec (236.14), temperature for fluid adjustment is 45C/113F.
Chamfered pan (green overflow pipe) cars made after 21JUN2010 (mostly 2011 model year up), Uses the new blue fluid spec (236.15), temperature for fluid adjustment is 45C/113F. Check your Mercedes build sheet https://www.datamb.com/ for option A89 (reduced friction) which calls for this fluid.

Check MB for compatible fluids:
https://bevo.mercedes-benz.com/bevolisten/bevo-sheets-sort1.html

Some cars are equipped with additional ATF cooler beside the integrated cooler in the radiator, look in front of the radiator for a small cooler that connects to ATF lines, this cooler has an integrated thermostat that only allow ATF flow above 90c.
If you have this option, modify the flushing procedure accordingly, u might have to leave the car warm up until ATF flow from return line, and when you are finished with flushing you might have to leave it cool down to below the checking temperature.​

Torque specs:
ATF pan bolts: 4NM + 180 degrees (if you decided to re use the old bolts, torque them to 4NM then set your torque wrench to 9NM and turn them towards 180 degrees, stop upon reaching the 180 degrees or 9NM which ever comes first).
Drain plug: 22NM
ATF return line E14 bolt 106 in.lb


Finally enjoy the video