I recently purchased a 2005 CLK 500 convertible with 54,000 miles. I do not know if the transmission oil has ever been changed. I am the 3rd owner. I have been advised that the oil is lifetime and should not be changed. I don't agree. I would appreciate anyone's opinion and the proper procedure to change.

You should watch one of Kent Bergsma's videos on YouTube. Here is one that is specific to your question:


I have found his videos to be very informative and sensible.

There are several schools of thought on changing your transmission fluid. I'm a big proponent of preventive maintenance and with other cars I've owned I've changed the fluid typically every 20-24k miles. Sometimes just dripping out a few quarts, and sometimes dropping the pan and changing the filter as well.

Of THIS particular car (I have a 2006 CLK550 convertible) it is a P I T A.

I bought the car almost 2 years ago with 13k miles on it and would've done it then, if not for the complexity. I now have 43k and REALLY want to do it, but I am toying with the idea of getting a new vehicle altogether. While I really LOVE this car, there are a few things that I dislike, and the complexity of changing the trans fluid is one of them.

IF I should decide to do it myself, I estimate it will cost me around $400 in parts/fluids and toold. The most expensive of all of these is the pump, which I estimate will run me about $180, and I may never have any use for it if I get a different car. On the other hand, if I keep the car at least another 10k miles, then I would end up doing the work a second time, and then I can see it as a justifiable expense.

WATCH THAT VIDEO and let me know what you thought of it.

I agree with Kent's assessment. I am handy, however, I cannot undertake changing the fluid on my own. I could choose 2 different possibility's, my mechanic that has been working on my cars for 25 years or bringing it to Mercedes. I have been buying Mercedes from this dealership for the last 35 years so I know the service department quite well. I could also do nothing and since I have a extended warranty for the next 3 years, I could roll the dice,so to speak.

You may want to also factor in how long you expect to keep the car. I usually don't think about getting rid of my cars - I somehow become attached to them. I think your better choice is the MB dealer that you already have a relationship with. It's NOT gonna be cheap! I am guessing a dealer in the tri-state area is going to get perhaps $400-$500 for the job, and I would expect that would include draining that catalytic converter as well.

When I mentioned that I estimated the parts/fluids/tools would cost me $400, that price included a NEW tranny pan. On my car (and perhaps yours) it is highly recommended that I change the pan to the 'new and improved' one. You should check into that.

By the way, I see you're in NY. MB in Paramus is very reputable, if that's convenient for you. Also, this is probably a very good time to get work done on your car, since they probably have a bit of lull in customers.

I appreciate your recommendations. The convertible is used in the summer by my wife on nice days. At most she puts on 3000/ year. I live on Long Island and use MB of Smithtown for service. I will probably drive the car until the warranty runs out. It will be 20 years old and could have additional problems. Please advise your opinion on draining the anti-freeze.

If it has a Valeo radiator, you may consider changing to a Behr before you change tranny fluid. Even if the orig Valeo was replaced with a "supposedly good Valeo", I dont trust them.

Tranny flush is a good time to change the wiring grommet...hey, was the tranny grommet defect fixed on the 7 speed trannys?

I just bought a 03 500 with 5 speed auto and did this last month. Seems wasteful, but now I can sleep at night. :-)