I have searched all the posts and cannot find if it is ok to use synthetic oil for the M119. Also would it be ok to use synthetic transmission fluid?

Of course you can use synthetic oil.
Here are M-B approved oils.
http://www.whnet.com/4x4/oil.html
For the transmission I would recommend M-B fluid from the dealer.

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2007 C 230 Sport.

You're either not searching properly or not reading through the results, people in the following threads have had success with synthetics on the M119....


What grade engine oil to use on aluminum M119?

Synthetic Oil - smoother and quieter engine operation?

Best fluids for 500E and E500?

John, I recommend Mobil 1 15W50 unless you're in a particularly cold region of the country ... Wisconsin, North Dakota, Montana, etc. Then you may want to use a lower viscosity oil for the winter months. Look at the pour temperature on the container of Mobil 1 15W50 ... you may be fine even in those states provided the temperature doesn't drop below 0.

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Fred Hoelzle

I seem to recall reading somewhere in the forum that synthetic may not agree with the hydraulic lifters or the special cylinder lining of the M119. I wonder why 15-50 is recommended for the M119. I would feel more comforatable using a synthetic 15-50 since that is a very thick oil on start-up.

Here is the thread. Can anyone validate this?

http://www.peachparts.com/shopforum/diesel-discussion/58911-automatic-transmission-oil-post359375.html#post359375