For the benefit of other DIY folks, I am posting here the procedure for the 4Matic front
differential oil change on my 2008 E300.
1- Warm up the car to operating temprature and drive around to get the diff oil to operating temprature too. This will make the extraction of the oil a lot easier.
2- Loosen front passenger side wheel bolts. Lift the car and remove front passenger wheel
3- Locate the fill/inspection plug. (refer to pictures)
4- Use an 8mm hex with extension
to release the plug. (refer to pictures)
5- Find a small hose that is small enough to fit into the tight passage of the fill hole. The fill hole may look big enough, but you will need a hose thats outer diameter does not exceed 5mm (approx 1/4 inch) and is flexible enough to bend at the entry of the hole to go down to the bottom of the differential. I got a cheap siphon pump and cut a piece and attached it to my suction hose using electric tape. (refer to pictures)
6- Extract the oil by maneuvering the tube inside diff case. Try to move the thin hose around everytime to think you have extracted all the oil until you get almost 600ml out. (refer to pictures)
7- Before putting the new oil, I used the jack to tilt the car to the driver side (by raising the passenger side a bit more). I did this to add som extra oil such that when the plug is closed, the oil will be just in the middle of the plug, and not below it. That's just my OCD :grin, and you can skip this step
8- This is a good time to change the brass washer on the plug (MB part number 007603-018101
). For the fluid, I used the MB oil part number 001 989 33 03 12
. (refer to pictures)
9- Pump the new fluid in and close the plug. (refer to pictures)
I did not use a torque wrench because it wouldn't fit in the tight space, but I think the spec is 14N.m.
*Note: If you want to use a different brand oil, use a reputable GL-5 spec oil. Do not use GL-4 in the diffs due to the high pressure of the hypoid gears. Refer to http://www.benzworld.org/forums/1450715-post2.html