Hi everyone!

Here is my experience about changing 4matic fluid for my MB 300E 4MATIC year '89:
Well, the fanniest thing I thought the liquid used in 4matic was the same as goes into automatic transmission HA-HA-HA how dumb I was. But, this gave me a lesson. Basiclly what happend was: I'd put transmission oil into 4matic container to top it up, went on a road , driving, everything is good day, two and then.... bang, 4matic light came on. After couple days of investigation I realised how stupid I was So...., had to think how to replace the fluid with the correct one.
1. on top of 4matic liquid container (plastic one) located cap with attached fluid pipes to it (return pipes for the liquid)
2. unscrewed them and connected clear plastic tube(s) to them, the other end placed into clear plastic bottle(from Coca Cola)
3. bought in advance CORRECT 4MATIC fluid (from MB dealer) 3L (3 bottles x1L)
4.opened them all(taken papercover from the top of each bottle) and put them next to myself(so they will be reachable when I'll be changing bottles)
5.started the engine(better do it with someone else P.S. I did it on my own)
6. quickly back to front of the car turn the SERVICE lever to off position
7.U will see that the liquid will start running into your bottle (you connected earlier)
8.at the same time look inside the container(actual 4matic container, not bottle), you will see how liquid going away. Just when the lower pipe will appear(on the bottom of container) pour the stuff you bought(4matic liquid)
9.level will drop inside container again top it up so pipe wount catch air
10.when you'll see healthy color of liquid going through your attached pipe to the bottle, thats means the liquid did the full circle.(give it a few seconds more till the color turns real goldish color. P.S.mine was red, because as you remember I put hydrolic liquid in it which made all liquid red)
11.here I stretched my arm to reach valve(which disables 4matic for servicing) on opposite side of the engine compartment, and turned it to normal position, thats made my clear pipe which goes into bottle turned red again for few seconds(note:engine still running) and then goldish colour again.
12.at this point I placed outlet pipe quickly into main container to keep it circulating (to avoid exessive waist of not cheap 4matic liquid)
13.turned engine off, secured all pipes back to its original place, (dont forget to put SERVICE LEVER to normal position), sorted

turned the engine back on, 4matic light still on
Went to empty car park, stand still, booted accelerator to the floor (give sensors impression that the car skidding P.S. As we know, 4matic engages front wheel drive only when sensors feels the difference of speeds between front and rear wheels. Well, that was my only idea I could make sensors thinking that car skidding (I dont have special equipment for doing it right way) anyway, after few RINGs I felt how front end started pulling me to straight line,making impossible to make wheelspin RINGs. When I stopped 4matic light went away, I restarted the engine, control lamp came on for a second (usual computer checks) and gone off. Sorted!!!
thats my experience, if its helpfull for someone I'm glad, but its worked for me (MB dealers asked sky price only for looking under the bonnet, F***'EM

GOOD LUCK!!!