Hi guys! At what milage do I need to change the transmission oil? And do I need to change it at all if there are no problems with the transmission?

 

I should be changed at every 40k - 50k miles, regardless of what the manual says. I know at first Mercedes said the 7G tronic was a "lifetime fill" later revising it to it needing to be replaced every 50k miles, as they started to experience problems. However, it is good to replace it every 50k miles. This will also need to be done at the dealership, and is not a typical DIY.

 

I just did my transmission service (pan flush) back in February. I went to an local indie and his work was perfect. I could feel significant improvement right away.

My car (w209) had been serviced exclusively by the dealership for the past 8 years and I was kind of nervous to go to an indie. So I monitored his work and he was very clean and meticulous. For transmission service, it is very important to keep things clean.

To answer the OP question, yes, you should perform the transmission service every 40k miles. Just like oil change to the engine, the transmission needs new fluid for lubrication.

 

mis3. Do you live in Southern California? Where is your local indie? Anybody know any good indie around So. Ca.(LA/Inland Empire area)?

(Mercedes said the 7G tronic was a "lifetime fill" )...same BS as BMW...hahahaha

 

I live in Toronto.

My w209's ATF was supposed to be "lifetime" as well. This is why my car does not have a drain hole and I did only pan flush. My SA used to tell me not to do the transmission service.

Actually, there is a few very well written DIY in this forum. I am not a DIY person so I went to an indie. My car is shifting so smooth now and the ATF pan flush got rid of the idle vibrations I used to have.

 

There is no such thing as lifetime transmission fluid any more, even MB dealers admit it now. It should be changed every 60K kilometers. I always recommend a partial flush (filter and transmission oil without TC) on the vehicles with "lifetime" fluids and full flash for those trannys having TC drain plus (e.g. 722.649, 722.9).
If your tranny is under warranty and it requires full flush, I would let MB dealership do the flash instead of independent shops to avoid warranty issues... (Not that I do not want your business, just too much hassle to prove to MB that you knew about the drain plug on TC )

Igor.

 

Servicing this transmission now requires a completely different process than its predecessors. When the transmission fluid needs to be changed, the fluid is pumped into the transmission through the same drain plug used to drain the fluid – not a straightforward process. The transmission oil pan has an overflow pipe made of plastic. This tube attaches over the drain plug and must be dislodged with a drift through the drain plug hole in order to drain the fluid in preparation for the pan to be removed. Only after the drain plug has been removed and the overflow tube dislodged can all the fluid be drained.

*New aluminum bolts are always used to secure the transmission and reinstall the pan.*

After the transmission fluid is drained, the six aluminum transmission pan screws can be removed and the pan lowered. The filter sits loosely on the valve body and can be removed by pulling down with slight effort. Once removed, wipe the sealing surfaces and press in the new filter. The transmission oil pan will need to be cleaned and the overflow tube reinstalled on the pan. Most pans also have a thin magnet on the bottom that will need to be cleaned. This magnet is used to capture small fragments of ferrous metal particles that might be present in the fluid from normal or perhaps premature excessive wear. A new pan gasket is installed on the pan and new bolts are always used to reinstall the pan.

Most weekend warriors would find filling and adjusting the fluid level to be frustrating. Because the transmission has no dipstick and upper fill tube, the fluid must be pumped into the transmission with a pump or fluid transfer tank. This requires special equipment. To make it even more difficult, the temperature of the transmission fluid is a critical element when adjusting the fluid level. Approximately six liters of special fluid are pumped into transmission. The engine is then started and transmission fluid temperature is monitored using the Star Diagnostic System equipment and increased to a specific temperature, depending on car model and its equipment. The filling device is removed and extra fluid drained until mere drops ooze from the drain plug. Finally, the plug is reinstalled with a new copper seal.

Please see the above bolded part. Having Star Diagnostics is a CRUCIAL part to filling the transmission to the appropriate levels. Even just a few ounces of too much or too few fluid could cause premature failure of the ENTIRE transmission, a very expensive repair... Furthermore, Star Diagnostics will help read the codes on the transmission which can help detect wear, failures, and other critical information. You're missing out on vital system diagnostics about the status of your transmission especially since the transmission can only store around 20 codes if you don't get the flush done at the dealer.

This is why I don't recommend Indie Service on the transmission. For oil changes and filter changes, sure, but not for transmission.

 

I suggest you watch MB dealer do the flush...
Any reputable MB shop has Star Diagnostics these days so it is not an issue. For the last 5-8 years MB vehicles do not come with transmission dipstick and any reputable shop has MB dipstick. Pumping oil through the drain hole requires the same tool as pumping fluid for your differential. Now, new screws and seals come as part of the transmission kit (if one knows what to order). Are you related to MB in any way ? Where did you copy/paste above from ?
I am sorry, but we did 10-20 transmission flushes of the C-class, including C63 and all of the above would only apply to "in-house professionals". Not an issue for fully equipped shop.

Igor.

 

Why do you suggest I watch the MB dealer do the flush? Also, I don't think its given that most Indies have Star Diagnostics. In fact, most of the Indy's here on Long Island refuse to work on Mercedes, let alone have Star Diagnostics. Furthermore, the ones that do have Star Diagnostics cost almost as much as getting service done at the dealer.

I am not affiliated with MB besides for Generation Benz, so I do sit in on some engineering chatter and have access to some documents. The above was an excerpt from a document written by an engineer with some personal input. I'm not doubting that some Indie shops (like yours) do a good/acceptable job. But the fact is, not many Indie shops do the "right" job, and Mercedes-Benz has very sophisticated services that Indies simply can't stay on top of it all. Alignments for one are one thing Indies can never get right on a MB because MB dealers have a special process and unique equipment.

 

My indie (Toronto) has the diagnosis tool which can reads the fault and warning codes. He also has the dipstick to measure the ATF level after the pan flush.

 

I suggested to watch transmission flush because it is not that complicated when you know what to do. I do agree that MB dealers are much better equipped, but good service tech. can do more without special equipment than average tech with all the equipment out there.

To the previous poster: STAR can do much more than reading codes. Most good scanners can read codes (e.g. X431), but there is more to diagnostics than fault codes. Also, WIS is a must - AllData or Mitchell do not have that information.

Igor.

 

Agreed 100%. Just like everything else, it all depends on the service tech.