Photo DIY- 722.905 "7G Tronic" NAG 2+ Transmission Oil/Filter Change

part 2

part 3

part 4

part 5

Last but not least!

Thank you G-AMG for a great post. My W212 probably has another year before changing the ATF but I need to understand the procedures upfront. After read your entire post, can I draw the following conclusions? (based on an engineering mind)

The bottom line is the car must be in a flat position and obey the 45 C degree rule

1. If the car is parked/lift in a flat position and the temperature of the ATF is at 45 C degrees (while engine running), there will be no or very little ATF comes out when remove the draining plug at the green raiser pipe.

2. There is no need to measure old fluid because the green raiser pipe will prevent from overfilling anyway - the magic of overflown concept.

3. If space is allowed to extend the green raiser pipe higher (require new design), it's possible to top off the ATF without having concern about under or overfill when the car reaches normal temperature (90 degrees? at least indication of the temperature gauge on my 2011 E350). This should be a new suggestion to MB.

lightfytr said:

Just found this, any feedback?

Mercedes W204 C Class Transmission Service ATF Fluid Oil Change 7GTronic 722.9 Test 0-60 mph - YouTube

Click to expand...

Very clever idea with limited tools - No wonder he is an engineer

I will do mine probably a year from now (only 23,000 miles) but I may change the ATF with cold engine. Here is the concept how to do it. Please let me know what you all think:

1. Jack the car up and use 4 jack stands to support. Don't care if the car is perfect level or not because it is in the same position when you drain and fill the fluid.

2. While the engine is cold, unplug the drain plug and collect every drop of oil and carefully measure it (figure out total amount of ATF above the overflow pipe at cold engine) - this is very important because the same amount of new oil will be pumped back in on top of other amount in Step 3. Assume transmission is not leaking or lost fluid earlier.

3. Drain the rest of oil from TC, oil pan, etc... and refill with new fluid similar to the processes that Stott and G-AMG did or use whatever method/tools you are comfortable with to pump the oil in. The question is how much oil is needed to pump in at this time? Let assume your car's transmission requires 9 litters then you take 9 subtracts to the amount you collected in Step 2 and add 1 litter extra to make a total. Besides your wallet and environmentally unfriendly, it won't hurt to pump in 9 liters at this time - assume your tranny capacity is 9 liters.

4. Start the engine to allow new oil filling up TC and circulating through the transmission coolant lines, etc. Shift all gears several times (using steering wheel paddle shifters if equipped) and wait for 10 seconds between gears to flush out any air pocket. Don't forget to shift neutral & reverse gears too.

5. Let the oil temperature cool down (similar to the temperature in Step 2). If necessary leave the car overnight to cool down.

6. With cold engine, open the valve on the filling nozzle/pumping fixture to allow excess oil above the overflow pipe running out. Similar to the Step 2 above but don't need to measure excess oil.

7. After all excess oil came out, while engine is still off, pump in the same amount of fluid that was measured in Step 2 with fresh oil.

8. Start the engine and wait for 60 seconds or so to allow the oil level in the pan dropping below the top of the overflow pipe (because the oil in pan is pumped up to TC and filled other parts), remove the filling nozzle (oil should not come out at this time) and quickly install the drain plug while engine still running. It's critical to complete this step before the ATF in the transmission reaches 45 Celsius degrees. NOTE: 60 secs is a guessing time for complete oil circulation but its temperature won't reach 45 C or 113 F.