First transmission service was done ~ 28 000 miles - previous owner
Second transmission services was done ~ 56 000 miles - previous owner
Third service was done by me at 96 000 miles - I got the car 95 000.

I don't think intervals were crazy high, but could be wrong?

If I have TC issues wouldn't that cause any codes to be record or drivability issues at all time?

So another drain and fill? I'm planning on ordering 6 liters this time...

Here in EU on non-AMG models we do transmission service every 125K km or 5 years for 089 models.

Why you buy 6? Although I am not sure about your model exactly, but I always buy 10 liters as 7G+ use like 9-9,5. Including Torque and radiator.

If you will still not find the drain screw on TC, you can take out the retour pipe ( the one that return the oil from radiator to the gearbox) and let the new oil push the old one till will become clean....after pumping enough new oil.

I would rather keep things simple and just do the drain and fill, as I did before

Checked Cam sensors and camshaft adjustment solenoids - I'm happy to report no oil in plugs!

Mixing fresh 6,5 liters with burned 4,5 or mixing another 6 over the newly mix it is not simple, more likely wrong....

How would ATF look like after 5 years or 125K km in Europe? I highly doubt it will be bright blue?

I said the ATF was dark, doesn't mean it was burned, burned ATF has a really distinctive smell. From all my online search - 40k miles (which was my last interval) is half the interval you mentioned 65k kms.

Correct, it's dark after 5 years.

Sorry about "burned", I should use "old" or " oxidated _... anyway, mixing could lead to foam or even marmalade.

Do you mix old with new oil on engine?

I don't want to argue, but you never really get all the engine out of the engine either... there's always a small amount left.

With the transmission it's a bit different, at least on my end, I really don't feel comfortable disconnecting that line, etc.

Is disconnecting the return line do drain all the fluid in the MB procedure as an option or just something you're doing out of experience?

It's MB procedure, you can find it in WIS.

​​​​​And it's not " all the fluid", it's only the part from TC and radiator. Start engine like 1 minute.

A small amount like some 100 milliliters over 9,5 liters.... acceptable of course.

Are you willing to share that procedure, I don't have access to WIS? Thanks in advance.

Did you remove the auxiliary oil pump from transmission, when you removed oil pan? I would use VIN to try again to find the screw.

No, that was not in the way, I just had a bracket on the front of the vehicle that was holding the wiring loom, hold by two bolts on. left and right side, removed that (or just leave it hanging) and dropped the pan.

I pretty much followed the procedure here:

That's why you did not find the TC drain screw, maybe

At first I followed these steps here:

Couldn't find the TC drain, so I just followed the other video.

The WIS procedure does not call for draining the entire system, i.e., the transmission cooler. The procedures for a fluid and filter change only includes draining from the transmission oil pan and torque converter if it has a drain plug. Otherwise, draining is sufficient. The service cycle for the newer blue fluid (ATF-134FE, MB 236.15) varies a little from year to year, but for my car and year it is 77,500 miles or 5 years. My car was 8 years old with only 43k miles when I discovered there was also a time interval recommended. The service was done by the dealership with parts I provided and no comment was made about the color or age of the fluid. Some people want to do a complete flush of the cooler as well by removing the oil feed and return lines, but a normal service does not include flushing. Unfortunately, the WIS does not state when and why to flush, only how. And with all the warnings about possible dirt/debris contamination when disconnecting the feed lines, I would be reluctant to do so unless there was an indication that it was needed.

Oxidation is caused by heat. Apparently, if the fluid never exceeds 170°F, the fluid should last 100k miles. At 190°F, about half that. However, my normal operating temperature of my transmission fluid is 180°F, so the 77,500 interval is safe.

@georgiuzunov should be fine with the intervals given without doing a complete flush. Though I have not used it, there is an adapter from CTA Manufacturing that uses low air pressure from an air compressor to force out all the fluid. It has fairly good ratings and is also offered by FCP Euro, whom I trust.

OP ..."should be fine with the intervals given without doing a complete flush.", but it's not fine...

OXidation came from long contact with the Oxygen

Of course if you drain the TC is not necessary to clean the radiator of there is no complaints....

I would not use air pressure inside the transmission, as inside is everything about.... pressure, pistons, brakes, valves, etc.

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My observation is that the auxiliary pump is for cars with ECO Start/Stop only since the pump is what keeps the transmission oil pressure at the necessary level for immediate engagement. Decoding his VIN, his car does not have ECO Start/Stop and, therefore, may not have an auxiliary pump.

Heck of a good call there. I would imagine disabling the stupid "Eco" start is one of BenzNinja's most popular "mods".

I have kept pretty out of this (PTSD from when I had the Trans Fluid changed in my 350). It was a three week long saga of leaking fluids, comical "smoke screen" miles and threats of lawyers......this all at a reputable Mercedes / BMW shop......

I agree, ideally, removal of all fluid is preferred, but not practical or necessary as long as there is no existing internal damage. Since there was minimal material on the magnets and no performance issues prior to changing the fluid, there is no indication of internal damage.

WRT flushing with air, it is done at lower pressure (~7 psi), which is probably less than the pressure used when Mercedes does a fluid flush. The CTA tool has been around for a long time. If there were problems, they would have shown up by now. The tool is also demonstrated on Legit Street Cars YouTube channel, beginning around the 23 minutes position.

Sounds like a good story. Did you post it somewhere or do we need to open an old wound? (j/k about opening the wound)

Before finding @BenzNinja I had spent hundreds, if not thousands, of dollars on diagnostic equipment and bootlegged software. I've mentioned before that I own or have tried more scanners than I care to admit (Autel MaxiDAS (2), iCarsoft (2), Foxwell, BlueDriver, Carly, and LAUNCH (3)). Most I still have, but a couple I returned or sold. I learned from that that BenzNinja really is the best deal for equipment and software PLUS diagnostics and coding services. He really is cheaper and of better value.

ECO Start/Stop is one of his most popular mods. But I had already spent over $300 to get the Mid City Engineering device to eliminate the start/stop on my two cars before joining the BenzNinja Club. I could have saved A LOT of money if I had discovered him years ago when I had my SL500.

Good idea, I didn't notice the VIN here. Indeed no Auxiliary Oil pump on this car, but the program shows the screw!!!


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Sure, but the drain screw/bolt and the auxiliary oil pump are unrelated other than gaining access to the drain screw.

As here there is very few 7G+ without Auxiliary pump in the EU, that's was my purpose asking about removing the pump, for gaining access to the drain screw.

Oh boy, please do not rely on pedal method to reset transmission points. Don’t confuse reset of throttle adaptation values with calibrating shifting ranges against the predefined torque parameters. Another point that I want to make is OEM fluids are great, if you like to stick to approved lists. But always keep in mind that the manufacturers sometimes tell you that transmissions can run lifetime they don’t want you to have ultra quality fluid to keep your car running forever. Make your own conclusions.