Changing fluid and solenoid O-rings
722.9 transmission fitted to a 2010 E500 E550 W212
7G-Tronic - VGS2-NAG3 in my case

1. Change fluid
2. Updagrade pan and filter
3. Replace solenoid O-rings

O-Ring specs
oil tube elec connector solenoid large solenoid small
cross section mm 2 3 2 1.5
internal diameter mm 7.9 31.3 14.7 8.7
1% stretch mm 7.8 31.0 14.6 8.6
5% stretch mm 7.5 29.7 14.0 8.3
Spec. gravity 1.4+ 1.4- 1.4-
I used (IDXCS mm) 7.8x1.9 30x3 14x2 8.5x1.5
(Viton 75)
how many 2 2 8 8

USA - Cobra transmissions do a solenoid O-ring set
https://cobratransmission.com/722.9-Solenoid-Oring-Kit

NZ AUS - Seal Innovations
https://www.sealinnovations.co.nz/#/product/category/Product_Group-O-Rings-O-Rings
Such as P008V75, OR014X2V75, OR030X3V75, OR008.5X1.5N70

Fluid - Mercedes approved brands
https://operatingfluids.mercedes-benz.com/sheet/236.14
https://operatingfluids.mercedes-benz.com/sheet/236.15

Other parts - these vary between models. I upgraded to a different pan

USA - FCPEuro do complete kits, such as:
https://www.fcpeuro.com/Mercedes~Benz-parts/E550/Auto-Trans-Service-Kit/?year=2009&m=20&e=5950&t=5&b=5&d=824&v=

NZ AUS - Alltranz do many parts including filter kits
https://www.alltranz.com.au/shop/drivetrain/automatic-transmission/Mercedes-Benz/722.9/

EUR - Spareto do many parts
https://spareto.com/t/vehicles/mercedes-benz/merce-e-class-w212-e-500-212-dot-072/transmission/automatic-transmission

Other bits and pieces
Lint free swabs https://www.aliexpress.com/item/1005002607049911.html?spm=a2g0o.order_list.order_list_main.34.25441802Xw8Y13

Pan fill adapter - M12x1.5 thread, then barb to suit your pump (I used 6 mm barb)
https://www.aliexpress.com/item/33052942866.html?spm=a2g0o.order_list.order_list_main.40.25441802Xw8Y13


Other links:
https://gearsmagazine.com/magazine/common-mercedes-722-9-problems/
https://www.youtube.com/watch?v=qv_To8rIfgk
https://www.youtube.com/watch?v=1LjBV3qRhP0
https://www.youtube.com/watch?v=FQcEutI1SeA

00:00 Intro
01:18 Parts selection
05:05 Raise the car
05:37 Drain torque converter
06:10 Drain the pan
08:28 Remove valve body
13:18 Choose O-rings
22:35 Reinstall
24:31 Fluid fill
25:42 Conclude
23:49 Verdict