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I’m planning to change the transmission fluid soon. I’ve read a lot of opinions on whether to do a flush or not. Most seem to lean towards not doing it. There are also opinions that flushing can be done in different ways.
I consulted two independent mechanics and a Mercedes dealer, and all of them include a flush when changing the fluid. I’m a bit confused. What would be your verdict?
Another question: I was surprised to find that independent mechanics charge at least as much as the dealer, or more. I live in Quebec. What’s your experience?
I’m planning to change the transmission fluid soon. I’ve read a lot of opinions on whether to do a flush or not. Most seem to lean towards not doing it. There are also opinions that flushing can be done in different ways.
I consulted two independent mechanics and a Mercedes dealer, and all of them include a flush when changing the fluid. I’m a bit confused. What would be your verdict?
Another question: I was surprised to find that independent mechanics charge at least as much as the dealer, or more. I live in Quebec. What’s your experience?
Just drain your torque converter, pan, and transfer case if you have the 4Matic. Drop the pan, change the filter, and fill it back up. No need to push air through the lines to get out that extra 1 liter, it really makes no difference if 10% of the fluid is old.
Here’s a sheet made by a fellow forum member on what parts you’ll need to service the transmission.
I’m planning to change the transmission fluid soon. I’ve read a lot of opinions on whether to do a flush or not. Most seem to lean towards not doing it. There are also opinions that flushing can be done in different ways.
I consulted two independent mechanics and a Mercedes dealer, and all of them include a flush when changing the fluid. I’m a bit confused. What would be your verdict?
Another question: I was surprised to find that independent mechanics charge at least as much as the dealer, or more. I live in Quebec. What’s your experience?
Originally Posted by hmclaughlin67
Just drain your torque converter, pan, and transfer case if you have the 4Matic. Drop the pan, change the filter, and fill it back up. No need to push air through the lines to get out that extra 1 liter, it really makes no difference if 10% of the fluid is old.
Here’s a sheet made by a fellow forum member on what parts you’ll need to service the transmission.
Transmission flushing is a decsion based on miles travelled and service history. How far have you travelled and what's the frequency of oil changes? Were they just an oil and filter change in the past or was the torque converter drained as well. A bit more information is needed if you can.
Transmission flushing is a decsion based on miles travelled and service history. How far have you travelled and what's the frequency of oil changes? Were they just an oil and filter change in the past or was the torque converter drained as well. A bit more information is needed if you can.
I bought a used car. I assume the oil hasn’t been changed at all. The car is from 2011 with a mileage of 52k.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
With a 2011 car, if it has the 7G (versus 7G+) transmission, the fluid should have been changed at 39,000 miles. If it does have the 7G+ transmission, the fluid still should have been changed at 5 years.
With a 2011 car, if it has the 7G (versus 7G+) transmission, the fluid should have been changed at 39,000 miles. If it does have the 7G+ transmission, the fluid still should have been changed at 5 years.
Exactly, and the manual states that the oil should be replaced only once. This raises questions because, as far as I can tell, people prefer to change the oil periodicaly.
Not sure why this is so complicated. It's the same concept of changing your oil. You drain the fluid, and then you re-fill the the fluid. And change the filter.
In the exact wording of the MB W204 service sheet: "Automatic transmission: Change oil and oil filter."
Now this second part may get really complicated - but ask them to drain the torque converter.
2011 Service Booklet. It says: "Service 20 - once at 60,000 km, or 3 years"
MB originally said these where "Lifetime fluids" - very short lifetimes indeed. Then they changed it. Some service books don't schedule a change until 60k miles. You need to understand that just dropping the pan and changing the filter only drains about half of the fluid. IF your car has a drain plug for the torque converter, you can get about 80% out. Not all do, as they changed it mid-production.
Drain what you can. If you don't have the TC plug, do it twice over a shorter period. 52k miles is at the far end of the range so best to do more frequent servicing. Flushing will potentially cause you grief. Unless it's been driven hard all its life, you should be fine. If you had 100k miles that would be quite a different approach. Make sure you use only MB spec fluid.
Last edited by BlackML550; Jan 25, 2025 at 07:13 AM.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Originally Posted by --mb--
2011 Service Booklet. It says: "Service 20 - once at 60,000 km, or 3 years"
I concur with what @BlackML550 said. 60,000 km is approximately 37,000 miles, which is the interval you want to use for the 7G tranny (not 7G+) which you have. To know for sure, enter your VIN on www.lastvin.com and look for Code A89. If you don't have it, then you DO have the red fluid (MB 236.14).
Also, it is important to know what equipment you have and how things change over the years. Always consider the most current information for your particular equipment. Mercedes is always updating information as they make improvements (referred to as "continuous improvement" in the systems management world). What is a little confusing for me is that my 2004 SL500 with an early 7G tranny did say to replace the fluid and filter about every 39,000 miles. It did not have a drain plug for the TC. This is the maintenance checklist for the R230. It says every 60,000 km (or 4 years).
Thank you, guys, for your advice.
In the end, I’ll go to the dealer. I don’t feel confident doing it myself, and I don’t have the space for it. For some reason, independent mechanics in my area want to charge me even more than the dealer. So, I don’t really have much choice. I’ll ask them if they can drain the oil from the torque converter, but I haven’t decided about the flushing yet. Most likely, I’ll also ask them not to do it.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
There are different means of flushing. One is with a cleaning fluid under pressure that forces the fluid throughout the transmission, TC, and transmission cooler. It involves a special purpose (expensive) machine and costly cleaning fluid. Another method is to use low-pressure (7-8 psi) compressed air to do the same. The compressed air method would clear the TC and transmission cooler (radiator) of remaining fluid after the initial draining. That might be OK and should cost very little or no additional charges other than 5 or 10 minutes of labor. There is no expensive fluid being forced through the transmission.
For DIYers, here is the adapter for the compressed air method.
Last edited by JettaRed; Jan 25, 2025 at 09:04 AM.
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