So i have a 2008 Mercedes-Benz E 200 Kompressor 5G-Tronic (W211). being aware of the theory that changing transmission fluid after having 135K Kms on the car will break my transmission/gearbox and finding it hard to believe, I decided to try it myself.
Why I am doubting this theory
My theory is about the origins of “transmissions breaks when fluid is changed”, and why it is likely WRONG.
The origin of that theory is probably the number of people who have problems soon after changing transmission fluid, and basically there is nothing wrong with the theory in this regard but bear with me.
my counter theory is, when people change their transmission fluid at such high mileage, they are not exactly servicing the car on proper intervals, the reminder to change the fluid for them was probably that the transmission acting up, so the transmission is on it’s last leg, you change the fluid, but the fluid can’t save the transmission, it is too late, the dirt in the dirty transmission fluid was creating a bit of friction (and accelerating the wear in the process), the situation is bad enough that you went to change the fluid to see if that helps, the transmission keeps on deteriorating because it is already going in that direction, so what do you do, you blame the oil change ! “It was working at least before I changed the oil !”
So my car comes with the 1.8L M271 , My transmission is probably the 722.695.
I have already drained 3Liters of fluid (All that was in the pan), and filled the transmission with 3 liters of Mercedes-Benz 236.14 transmission fluid, I have also replaced the oil filter and the pan gasket. there is a magnet stuck to the pan from the inside, be sure to clean that too !
Later on, I drained another liter and a half, and added a liter and a half, and kept half a liter to top it up once i find my relevant dipstick (Does not come with the car)
There are alternatives to the somewhat expensive MB fluid, but since i couldn’t find an MB certified one, or at least a fluid that claims to be the same, I decided to bite the bullet and go with the original.
UPDATE: After one year (today is April 19 2024), the transmission is working exactly the same as it was before changing the fluid, things seem to be going just fine.