Hello everyone,
So I decided to change my transmission fluid at 45k. I read many threads here and when I went to do my transmission, I am having a problem with the TC drain plug.
So I kept looking for the rubber cover, and finally I was able to locate it on the driver side of the bell housing. However, it is a square shape cover and the drain plug is impossible to loosen from that angle. Any ideas?
Thanks

Try one of the other inspection plugs. There isn't a great angle to access it though, it requires a ball-end allen most times, and be careful taking it out.

Thanks man....I am unsure what you meant by other other plugs?..

There are several caps/covers on the bottom of the trans, should be more than one. If you can see the plug though, you're probably at the right one. It's not easy to get at, it's right on the edge of the opening and it's a small plug. They don't really want you messing with it, I guess.

FYI the service interval for these is 70k miles. Turning the engine by hand will move the TC plug, give you a better angle. Haven't done it yet myself but everything I've read or watched mentions that. I purchased my 13 C300 with 47k miles on it and was going to do it until I saw the service recommendation from MB. I probably won't wait to 70K miles but at least now I know I have some breathing room.

Not a bad idea to do it early, when we do the services at a lower mileage, the fluid is usually quite brown, no longer it's blue color.

No evidence to support my theory, but I'd guess they just picked the 70k mile interval to put the car well out of warranty period before you have to open the trans. Reduced cost to MB. The transmission didn't change mechanically, and just using a thinner fluid can't magically make it last longer. Temperatures and contamination loads are the same.

True it is 70k service interval, but I like to keep my car in top notch. Also, just like you I did browse and saw all the articles here...It seems to me there is a change in the bell housing design. The rubber cover is square, small and on the top passenger side of the housing. You will be able to turn the engine and see the plug, but I sent two hours trying different tools in order to be able to get a grip of it with no success. What I am thinking that I will do tomorrow is using a small Allen that from the way it looks, will clear the housing and get the plug. I will share some pictures tomorrow when I go under again to better share with you guys.

Also, does any of you guys have access to WIS to look into that?
My vin is WDDGF8AB8DR284593

Appreciate it.

I work on all my cars and at times other people's cars. I took one look at the TC plug and I knew this isn't something to mess with. Like someone mentioned above, MB did not design this so that your average DIY could service it.

I drained all the fluid I could and left the TC alone. Man's got to know his limit. lol

Nice explanatory video for flashing the TC fluid can be found here (at 1:49):

^^^ not the same on 2013 C300 4matic Sport. If it was, we wouldn't have this thread.

Tell me, if you should manage to loosen the plug, and it slips out of the allen key, how do you recover it-?

extractor + new set screw plug + washer

or use a better hex tool.

Well it was a really hard job. The bell housing does have two rubber covers. One of them is on the top passenger drive above the exhaust pipe bracket. For this one, you will need to take off that bracket totally to get access. Once you r there and removed the cover, rotate the engine till u see the drain plug. Only this that worked with me was an Allen wrench due to accessibility. It really did take me sometime. Once out, you can retain the plug (if it just happened to fall in the housing using either your finger, or a magnet. In my case it fell right out.

In front of the transmission pan toward the front of the car I needed to remove a part (I really don't know what is it called), but it has a connector attached, and once removed with 3 screws, I had oil coming done. behind it is the other rubber cover, which you will line the torque converter plug straight down to empty anything left.
Once done, you rotate a last time to align the drain plug hole in the 10 clock direction to install the new plug (I used some grease on the head of the plug to get it to stay with the Allen wrench, then got it installed..very tight space) and put the rubber back.

The only problem is having the right tool to get that plug loose.
I hope they would make or if there is a special tool to get it done quicker. But I was successful.
I used Ravenol M 9-FE which is approved by MB for this transmission (Blue color). You can find it at Amazon, it is made in Germany and much cheaper than the genuine. I also used the Mityvac with its MB adapter to fill the transmission with no issues.
Needles to say, but even though MB recommend changing the fluid at 70k, I did my change at 41k. Fluid is still with same color. However, the filter and magnets were so dirty. So for a preventative maintenance, it worth the time and money.

Tell me about it. It looked like a pain in the *** compared to mine.

You removed the auxiliary oil pump? I never tried that. The older transmissions didn't have that and had a plug straight down, so it makes sense.

I beleive that was it, as I removed it, tons of oil came down. and behind it another rubber cover....
Do you know guys the interval for changing the coolant and power steering fluid?