Hey Fred - I see that you are nearby. I live in Concord!
I just bought a 2002 e320 and it has 140k miles. I have no history on it. It appears that the transmission fluid is ORIGINAL and has not been changed from the looks of it (original cap still on the transmission fill hole). My question is - do you think I should risk doing a drain/fill of the pan and replacing filter in transmission at this point? The car shifts okay (not as smooth as it probably should in my opinion) but I'm afraid of tampering with the fluid and making it worse. Any feedback is appreciated. I've been reading all about this on this forum and everyone has a different opinion......
At 140K miles you are not too late at all, my friend bought a 2005 E320 4M back in 2013 which is mechanically the same car as W210. He got it at 125ish miles, I’ve done a filter&gasket job for him at 136 or 138K something like that, interestingly the fluid in the car was yellowish color, we did not have any history so we drained and filled and drained&filled again twice after driving half hour each time so we got all that yellow crap out, I even posted pics here after break open his filter. 2 years later in 2016 we did another filter&gasket job at 216K miles and just last week we did another one at 305K. That car is a trooper.
I got my W210 in 2010 60K miles on the clock and my first job was a filter&gasket job at 65K, then at 84K I’ve done a fluid exchange aka Yumling Method here, it is in Stickies. Then fluid&filter&gasket jobs at 105, 120 and 141K. And just today I’ve done another filter&gasket job at 176K along with the belt and idler pulley.
As a side note; after completely changing out his fluid back in 2014, I let my friend drive his 4MAtic the first time and he kept going “oh woooww, oh woooww” every time the car shifts.
So I definitely say go for it and you’ll see the difference. I personally don’t like the flush idea especially at that mileage, I’d rather go baby steps, you can do a filter&gasket job now and another one in a week or so, just my $.002