I thought I would go ahead post the ATF oil sample results from my wifes C230 because I know it's been a widely talked about topic on this board as to how often to change it so here are the results. Just a little background on this sample, it has 29,750 miles on it with a total of 60k miles on the car. I've changed the fluid and filter twice before this, once at 1500 miles and then again at 30k miles. The torque converter does not have a drain plug in it so at each change I get about 4L out of it. The first column are the actual readings and the second column is universal averages.
Here are the comments from Blackstone Labs concerning this sample:
DALE: We didn't find anything unusual in this sample from your Mercedes' transmission. Aluminum
could be considered a bit high in relation to the other metals, but it's not high enough to show a
problem. We think this oil probably could have been left in place longer. No moisture or excessive
insolubles were present, and the viscosity was normal for ATF. No problems found.
It appears this fluid was in great shape and could have gone much longer. And of course for those of you that know my driving habits know that this car is not babied in any way when I get behind the wheel