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9 Posts
Discussion Starter · #1 · (Edited)
Very strange thing happen when I change the transmission fluid:
First I mistaken transmission pan as oild pan, so I drained the transmission fluid ( about 2.5 Quart). Then I overfilled my oil tank about double oil. Luckly I found the mistake ( I just drive a few yards in and outside garage), so I dump the engine oil and correct the normal quant. Then I bought 3L MB transmission oil (the right stuff from dealer cost 90) and filled to the filler ( behind the engine on left side of firewall -facing engine) about 2.5Q. When I test drove, I notice delay in changing gear, so it revv a lot. I thought might be not enogh, I put in all 3L, now still same problem, sometimes after a little drive better. I wnet to bought a MB dipstick, and it showed I way overfilled, so I drain 3times about 2.0 q, still showed overfilled with stick. This is impossible, and now the gear even can't get in, it just revv without engage. I refilled the drain ( I drained to original container) , now still same. It won't gear in like no fluid was filled.) I also noticed the drain is yellowish brown color, the MB auto transmission oil is red. Am I missing something here? Is that I filled in wrong filler? I checked web no picture showed the filler position, but on of old MB c240 97, at about same position with smaller engine block. Please help, any experiened appreciated.

13 Posts
Wow. I'd say at this point, tow your car to a competent shop and see whats what. While I'm a big advocate of DIY'ing, I also may spend weeks (spare time) reading every bit of info I can find before actually perform
an maint. operation or repair like a tranny flush.
DIY is not for everyone, you can end up costing yourself a lot of money.
I cut my teeth on VW's, FIAT's, Toyota's, old BMW's and motorcyles before ever attempting anything on a mercedes.
I'd sneak into the service area's and pick the mechanics brains when no one was looking. I befriended a mechanic who taught me much, and I read read read everything before even contemplating doing my own work.

I feel your pain, but you need to get your car to a shop ASAP and show them
exactly what you did and didn't do.

There is a plethora of things you may have done wrong.
Draining 6 quarts of the 8 that it holds of tranny fluid is a start.

Putting fluids in the wrong holes, another.
Not knowing how to properly read the tranny dipstick, yet another, or
knowing if you have the right dipstick...
being unsure of which part of the car is the transmission and which is the engine from underneath, another.

I wouldn't dare try to advise you at this point, What a mess.
You are brave to ask the question in this forum.

Hire a mechanic.

But to answer a couple questions:
Yes, the AUTO tranny filler is in the back, small hole, when you drain it can appear yellow or green from age. But when you put fluid in you need to let it idle for a long time, and let it circulate.

Whatever you drain, put back the same amount period.
If you drain too much you'll fry the tranny fluid pump.

After you fill, let idle for a few minutes, take a drive around the block, get the engine up to 80C and then check with the tranny dipstick.
There's photo's around here of how to read it.

It's a wet sump type of thing, fluid gets pulled from the pan, and then circulated throughout the tranny.

If you get air in the system, it also can fry the pump.
722.6 has a very specific and intricate fluid change method. Fluid has to be checked and level at 80*c and you must use MB special tool "dipstick" to adjust. Tow it and pay the dealer $180 or so to do the proper change else set aside $5k for a new tranny

2000 Mercedes-Benz S500. Sold: 2000 C230K, Sold: 1997 Porsche 944S
1,271 Posts
You DOUBLE filled the Engine Oil? Horrible, just plain horrible. Your system was way over-pressurized with Oil. I would not be surprised if soon, or later down the road, you have leaks in the Engine because of Blown Seals.
You did quickly correct it, but I would not be surprised if damage did occur.

Moving onto Transmission, It would be preferable for you to change out the Tranny Oil like you did, but ALSO to REPLACE the Tranny Oil Filter.
That's important. The Filter.
Leave car in Park, and leave on for 5-8 Minutes on LEVEL surface.
You can check your Oil Level then.

You may not actually be overfilled. At first you did. But it sounds like the Oil backed up into and up into the Tranny Dip Stick.
Let it settle for 5-10 minutes. Then very carefully check.
Its hard to see the level mark.

Make sure, 100%, beyond dispute you actually are filling the right dipstick tube.


2003 C240
46 Posts
I have a 2003 c240 also. What is the recommended milage interval for tranny service?
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