kavadarci

Hi,
Did my differential oil change and it was a breeze, oil was nasty, I only have 37000km but the age is there I guess 2012 c350 coupe.

I want to do the transmission next.
I've read the thread about the transmission oil change but I'm not clear on few items:
1. How do you drain torque converter?
2. How much oil do I need?
3. Is the overfill pipe closed with something and do I add oil through the pipe?
Than you.

IGB

This thread is posted in the W203 forum so I am not sure if this is the one you've read. If it is, draining the torque converter is outlined in the pdf titled: "Drain transmission oil from torque converter.pdf "

You will need 9 liters of transmission fluid. Make sure you read the related document to help you determine which fluid you need to get.

It is not closed with anything but it is set up to only allow a certain level of new fluid after which it would just leak back out. Of course to drain the old fluid you would have to use a special tool (or find something similar) to knock the overflow tube out of position to allow for the majority of oil that is in the pan to drain out.

Read the 6 documents attached to the thread I linked above and the procedure becomes crystal clear.

Good luck.

kavadarci

Thank you.
I just looked underneath my car and there is no sign of overfill valve, where should this be located?
Is it different on 2012 models?

IGB

I could be wrong but I do not recall any mention of an "overfill valve" in any of those documents in that thread!

The term "overfill' is used only in conjunction with "tube", and with that in mind, the "overfill tube" can only be seen when the oil pan is not bolted to the bottom of the transmission.

So in effect, you drain the old transmission fluid from the "drain hole" and you fill the new transmission fluid from the same (drain) hole as well. (This is unlike the differential where you have one drain hole on one side, and a fill hole that is higher but also on the opposite side).

dennish

The above sticky has all the information needed also.

Josh.A.Hussey

You wont see the tube by looking under the car, it is to be knocked off once youve undone the drain plug and allowed it to drain a bit.

kavadarci

Ok, how much pressure is required to fill the transmission with fluid through the drain plug?
I just talked today with Mr. Transmission and they don't even plan to empty the torque converter.
I plan to do it myself.

Colin G

Just got this done at the dealer. Transmission service and rear transfer case.


This is my first 4 Matic so I am unfamiliar with them. Is there also a torque converter up front I must change the fluid on? I am pretty sure the dealership told me they do not service the torque converter.


I assume about 1 lite of hypoid? Is there a DIY post about this somewhere on here? I would like to do this asap since the transmission fluid and rear transfer case just had the fluids changed.

Colin G

Found some info here.


https://mbworld.org/forums/c-class-w...ic-owners.html


Looks like I have to suck old fluid out and replace through the same spot.

twowheelin

Some interesting 7G-Tronic workshop advice from MB: http://www.google.com/url?...blah blah... blah...bv.132479545,d.amc

There is a good description of the trans fluid level checking on about page 34...

kavadarci

Guys,
I might not be getting something here.
I've changed transmission oil before on other cars but always filling up from the top.
I don't understand this overfill valve, does that come with the new kit? Is it attached to th oil pan?
Do I need another plug in valve to fill the case with oil, does that come with the kit?

Mercedes want 500 bucks to replace the oil. I know I can do it for less once I sort out this valve thing.

Thank you

IGB

Sorry, but my guess is that the parts you are not getting are those same parts from the linked documents that you have not read as of yet.

One thing that leads me to think this is that you keep calling it a "overfill valve" when in fact there is no such thing as a "valve". Its an "overfill tube". Now, even if you did not understand the purpose for this overfill tube from the one document that mentions the older version, the clear, simple explanation that is included describing why it was modified, descrining it by size (length) and color, would help clear that up.

An important thing to keep in mind here, (and again, not to be an ***) but this is a procedure that consists of so many steps, each one even more important than the other. Skipping one step or doing it wrong (because of a simple misundersranding) can and likely will lead to some transmission trouble, possibly transmission failure. So if for whatever reason any of these steps is not clear, it would be in your own best interest to get someone to do the work for you.

For anyone to accurately answer your questions, we would be copying and pasting information from those documents. Slip the middle guy and get the info from its source... Read the pdf documents in the theead linked above.

A new OEM transmission is in upwards of $8000... So one single and simple mistake could end up being a very expensive one!

Good luck!

twowheelin

See page 34. There are diagrams and pictures that will make this topic very clear! (Read the other docs too...)

http://www.google.com/url?sa=t&rct=j...32479545,d.amc

playstrings

Quality parts are $100.
Here is a video to consider.
Took my car to a reputable INDY for trans service, idiot tech was careless and STUPID.
I do it myself now, at least if it is an $8000 mistake it is mine.
Scotty does a number of good DIY videos. Enjoy