adding diff oil in a 86 190E
 

Anybody know the procedure for adding or changing the differential oil on a 86 190E? Thanks

unscrew the fill bolt (1st!) then the drain bolt on the differental. Once its all drained out, screw in the drain bolt and fill with your favorite brand of gear oil (75w90 or 80w90) until its full (ie. fluid coming out of the fill hole). Screw the fill screw back in. Wash floor and hands with degreaser.

The fill/drain screws are a 14mm hex key (I think...thats what they are on the 124 anway)

yup...14mm hex (Allen) socket or wrench is required.

One other thing to note is make sure you get the right kind of gear oil. LSD differentials require a special kind of gear oil. But im not sure what kind of differential you have because all you said was that you have a 86 190E.

One other thing: I'd shoot some WD40 or better penetrating oil on the bolts 1 or 2x a day for a few days (a week even) before you even attempt to get the bolts out. It will make your life MUCH easier, and you'll have to use fewer 4 letter words to get them out.

One or two more things.....

1.) Don't over fill it. I'll find out the diff. oil capacity (1.4Q on w210). In case, you can't, then collect the drain and refill with the same quantity.

2.) If possible collect every drop of fluid, that gear oil smell is almost impossible to get rid off. Watch out for your clothings and the garage floor.

3.) Refilling may not be as easy. Therefore I suggest investing $5 in a hand pump. Makes getting the oil in much easier.

4.) use socket extension for easier access, and pipe extension to make getting out the plugs a piece of cake.

I use mobil 1 full synthetic gear oil of the correct grade as stated in your manual.

is the filler on the top of the diff a 2 inch neck with a mini radiator cap on the top? if so does it just snap off or is there a procedure? Thanks, Ryan

NO-- don't try to open that (on top), it's a just a breather !!
 

The fill opening is about midway up on the drivers side of the differential body and requires the same allen tool as does the drain (which is located at the bottom). You can't easily overfill it if the car is relative level because the oil runs out the large fill hole as fast as you could pump it in.

You should purchase a small hand pump, available at most generic auto parts stores for around $5.00 US. It will make the job cleaner and easier.

DanielW

Did you catch the advise Skiier stated--
 

about being sure you can open the fill cap FIRST. It would be a bummer to drain out all the lube only to find that you could not get the "filler" cap to unscrew. You sure could not get new lube to pour in from the bottom!!! Can you spell TOW-TRUCK?

Good jack stands should be used because you will have to be under the car and tugging hard to get the drain and filler caps to break free and turn.....Don't let a car fall on you.

It's not that hard----but sounds like you've never done this service before. Let's be safe.

DanielW

Never a problem to undo the fill plug.

It's a soft alumium washer on a steel bolt. Quite a bit of static friction to overcome. I ussually hit it firmly with a 1-1.5# ball peen hammer. The shock will allow easy removal.


Michael