paperplane94

I know the ATF is supposed to be a lifetime fluid, but has this fluid reached the end of its life?

I placed the sampled fluid onto a facial tissue. Shouldn't it be red in color?







I inserted a clean flexible cable into the "MB workshop only" dipstick tube. I wanted to see the quality of the ATF and I am not pleased.

The shift quality feels OK, nothing apparently wrong. Sometimes it will stay in a gear for an extended period of time, but nothing too outrageous. I would just ease off the accelerator to let it upshift.


I need advice. Should I be looking to drain and re-fill the transmission fluid or is this just normal?

yourbenztech

It is long over due..change it now and I would recommend to replace the conductor plate as well!

Maj. Dundee

The color is not that important. It is what is in the bottom of the pan. Drop the pan and inspect the residue.

paperplane94

OK Thanks Guys.

I am confident that I can do the change and drop the pan.
The only thing I am not good on is how to accurately check the temperature when I go to refill the thing.
What is the easiest way to obtain a good reading? Can I use an existing sensor in the transmission?
I have absolutely no scanning equipment except for a DVOM.

DrX

I advise you to thoroughly research this task before embarking, to avoid the problems this member on another forum had.

If you are only going to empty the pan and refill, then the original fluid in your system is ATF 3403 from MB sheet 236.10. Since then, that specification has been superseded by a newer fluid called ATF 134 (from sheet 236.14). It might be OK to mix them, but it's better to flush the old fluid out using 14 L of ATF 134. The old spec ATF is still available.

P.S You don't need to replace the conductor plate. Yours is working just fine.

Driver55er

Use an OEM filter. I had an issue with an aftermarket german made filter popping off the valve body after a few months. It is a press in type filter and I found that they all don't fit as snugly as they should (either tube or o ring diameter was off).
My INDI that checked it out after I thought I had a blown tranny said he found it on the bottom of the pan. He only uses MB filters because the clearances are specific and tight.
Worth a few bucks not to have an issue like mine.

Change is pretty straight forward if you are DIY.

Driver55er

If you have a later model like my 03ML350 you do not have a converter drain plug. The only way to replace all the fluid is by dilution method of 4-5qt change driving and repeating or by opening a return line and starting the car draining x amount and filling x amount until you reach amount you want to flush. This is a pain and dilution will be simpler.

Also I remember reading MB uses graphite clutches and this causes the fluid to get more of a grey color. I always thought brown=bad for t fluid. In any case time for a service.

PS also you probably want to change the electrical connector while you are at it. This is a know problem leak point for our trannys. Connector is cheap.

paperplane94

Thank you guys, but I just went to the dealer and the service advisor gave me the old myth about "if you change the fluid, your transmission might fail prematurely shortly after." He was saying how clutch residue is suspended in the fluid and is helping it shift and that if it is changed, it will start slipping. He also said that since the transmission was made to be a sealed unit, the fluid should not be changed.

So now it is should I listen to him or not...

The car has 107,000 miles on it and the age of the fluid is unknown.
Do you guys think that the clutches have worn down and are now suspended in the fluid preventing it from slipping?

The SA was adamant, but do you think 107k miles is "too late" for a fluid change? it shifts normally with nothing extremely out of the ordinary.

Is my best bet to drain a quart or so from the drain bolt and examine the fluid and go from there replacing the lost quart with the ATF 134?

Please sway me as i am skeptical after what that Service Advisor told me.

DrX

Have a read of this to help you decide.
http://www.benzworld.org/forums/w163...ml#post5550132

What did the SA advise you to do? Spend thousands on a new tranny?

The "if you change your fluid, your tranny might fail soon after" idea is very popular, but has little basis in fact. I suspect that they get old, and fluid gets changed, and they inevitably fail. But just because event A preceded event B, doesn't mean that A caused B.

To answer your original question, the fluid is red because of a pigment. Eventually, pigments decompose over time.

yourbenztech

BTW if you don't change the oil sooner or later the check engine light will kick in for faulty trany..the residue collects around the conductor plate because it's heavier than the oil and mess up the communication which results in long shifting etc...

yourbenztech

I have to disagree with the Benz tech! If what holds the transmission together is bad oil than you might as well change the transmission!! The oil travel through many little tunnels throughout the transmission and there are many different valves, the purpose of the filter in the transmission is to collect this debris so you have a cleaner and smoother shift and have the transmission functioning acording to its optimum condition, the reason for the system being close is to prevent from most people changing oil on the transmission themselves because, not like motor oil, it is quite easy to blow a gasket on transmission if you over fill it or so....with that being said the wear of transmission oil is not as frequent as motor oil since it does not work on same temperatures however, transmission needs maintenance!!!!like any other machine, and I would recommend replacing the oil/filter/conductor plate/13pin transmission connector/gasket, and if the transmission is in good shape, you will get many more miles on it. Cost of oem parts is about $300 with about 2.5 hours labor.

paperplane94

So did Mercedes Benz put out a Technical Service Bulletin on changing the transmission fluid?
Because it says in the owners manual that the transmission is filled for life.

If any of you have the bulletin I would like to see it to see what they had to say about the "Lifetime Fill" Fluid.

yourbenztech

First, take everything with a grain of salt, even if Mercedes says "don't" they may make mistakes too....they had recalls, right?? Second don't forget that MB is a "for profit" cooperation" third we are not talking about the life of the transmission, we are talking about extending the life....and if your transmission is at the point of reaching the end of its cycle, there are things you can do to extend it that may be against the profit intentions of the manufacturer...capish??

DrX

Here's the diagnostic manual from June 2000, with page 11/2 relevant to your fluid colour question.

paperplane94

OK Guys, Thank you very much.
I have thought it over and I have decided to perform the ATF change using the info already here on the forum.
I do plan on keeping the car for an extended period of time and it would be nice if it had the original engine and transmission too. So I think this is necessary for mainteneance.

yourbenztech

Good luck and keep us posted so other people can learn from the experience as well.

zeduebel

Hello Guys,

I did my tranny flush a week ago, replaced with Marcon V. Works great ! Put it 4 quartz of tranny fluid. I drove 500 miles after my flush, and my fluid is now back to brown color. Probably needed a complete overhaul replacing filter and gaskets and connectors.
Thanks to forum, I had the courage to DYI this time on my tranny.