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(W211) DIY Guide for Differential Oil Change

Discussion in 'Engine, Drivetrain, Fuel and Exhaust' started by Knightkiller, Mar 22, 2012.

  1. Knightkiller

    Knightkiller Member

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    Joined:
    Nov 17, 2011
    Location:
    Chester, UK
    Your Mercedes:
    W211 E220 CDI Manual (07)
    Hey Everyone,

    Information was a bit thin on the ground for changing the differential oil so I wanted to pass along my experience from doing the job for fellow DIY'ers.

    A bit of background - we run a chauffeuring company in the North of England, and our cars do around 10,000 miles per month, so rest assured this DIY on changing the diff oil is well tested.

    Tools required:

    Differential Oil - Duh! I used Fuchs Titan Sintopoid FE 75w85, but check out the section on oil below to confirm which your car needs.

    Ratchet with a 14mm hex bit - Thats the one with the 14mm hex part poking out ;)

    Alternatively 14mm allen key - With a reasonably long extension (this is my tool of choice for this job)

    Drain Pan - To drain the old oil into.

    Suction Gun - Something like this to fill the diff with new oil.

    Also, depending on how rusted in your drain and fill plugs are, some dismantling fluid, such as plusgas, will make your life a whole lot easier.

    1. Oil - Which to use? After some research (check out the MB 231.1 spec sheet for some enlightening info on W211 fluid specs) then I found the sheet 235.7 is the correct spec sheet for our E220 CDI (and for a lot of other models too)

    As a side note, the old fill from factory was from the spec sheet 235.0 which reccomends a 85w90 oil, however this has been superseded by the 235.7 spec sheet which has only 3 oils listed. The original MB oil with part number A 001 989 33 03, Fuchs Titan Sintopoid FE 75w85 and Mobilube FE 75w85. (The MB oil is actually the Fuchs Sintopoid oil but in an MB branded container, and is the factory fill fluid since around 2007)

    So the oil I went ahead and ordered was the Fuchs Titan Sintopoid FE 75w85 fully synthetic gear oil. Personally I ordered from Opie Oils, but of course use your supplier of choice. :D

    2. To get the most accurate level when filling you're going to want the car to be level. I tend to drive the car up onto ramps at the rear and then jack the front so it's level. Please remember to use jack stands and leave the car in gear with the handbrake well jammed on! ;)

    3. So from the rear end of the car, you're looking for the differential. Its the small box like object which has three shafts leading into it. One from the engine to feed power into the differential and then one shaft leading out each side, feeding power to the wheels.

    4. Ok so time to check out those drain and fill plugs. The old rule here is to remove the fill plug first (the upper plug - located on the left-hand/nearside/passenger side of the diff for UK right-hand drive cars). Just in case we can't remove the fill plug or it rounds off or something, then at least we haven't drained all the oil out of the drain plug with no way of refilling it ;). Usually they have accumulated some crap and rust on the inside, so make sure to clear that out so your hex bit/key sits fully in the plug. For reference, they should go in about 10-15mm to be seated properly.

    5. Wow - these bad boys are on tight! And usually they're rusted in to make things even more helpful! This is where a bit of dismantling fluid around the plugs a couple of minutes beforehand makes life a bit easier. These are standard threaded plugs so left to loosen, right to tighten, so hammer away at those plugs till they come free, making sure that your hex key/bit is fully inside the plug to avoid rounding them off.

    6. Depending on how warm the diff oil is, you may get a dribble out of the fill hole, you did put paper down though right? ;). Have your drain pan ready to catch the fluid when you undo the drain plug (the lower of the two plugs on the right-hand/drivers side for UK RHD cars). Watch that horrid cruddy old fluid drain out with a smile of satisfaction. There's only a litre or so in there but make sure to let it drain fully, so go grab a cup of tea/ beer/ microwave meal. You may want to clean up those drain and fill plugs a bit now they're out of the diff. I tend to pour the drained fluid into a measuring jug at this point to see how much oil has come out, this will give us a good guide to how much should be going back in.

    7. Time to refill the diff. Remember to replace the drain plug - we all know a "friend" who forgot to replace the drain plug before trying to fill the oil right? :cool:. The Fuchs bottles of diff oil comes with a trick little spout but this is of no use for the suction gun so I unscrewed the lid fully and sucked the oil straight out of the bottle (make sure the suction tube is clean). You'll find the best way of crawling with the suction gun Vietnam style yourself, but your aiming to get that tube in the fill hole.

    8. Fill the diff until oil starts to dribble out of the fill hole. This is the reason the car needs to be level, so we get the level of oil correct. Cross check this with the amount of oil that came out, anywhere within 100mls (minus spillage :lol:), of this figure is pretty dapper old boy. Go ahead and replace the fill plug.

    9. Congrats, your done! Lower her down and go rack up some miles! :cool:

    Joe.
     

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