40 K miles should have been changed. I now have 60K on it. It is shifting rough on low speed downshifts and I thought maybe a fluid change would perk it up.. Of course it could be the B1 or B3 clips have let go also.. I would think that a fluid change at 60K miles would be a good thing but it almost looks like MB has made it a difficult task.

Lee, correct 30K miles on the non-electronic transmissions.
platt-, yes they evidently didn't quite get through to people to not mess with the transmissions on Mercedes so have gone an extra step to make it harder for the masses to change tranny fluid. I swear at some point they'll require a special tool to open the hood!

That is when I go all Mad Max on Mercedes-Benz, buy all the W124s within a 20 mile radius, and clean out every site online for spare parts. :D

ILUVMILS is completely correct. What I said previously is what some people do with the 722.6 transmission, the 722.9 is a completely different beast and must be dealership serviced.

Today against advise here, I went ahead and changed the ATF in my S550. Easy! no big deal. Drained the TC,Yes there is a drain plug on it, got exactly 4 qts out of that. Removed the pan drain plug and got less than a quart. I stuck a 1/4 steel rod into the drain hole and tilted it sideways. The overflow pipe popped off and 3 more quarts drained out.
Took the pan off and cleaned it thoghly, cleaned the 2 magnets, put the plastic overflow pipe back onto the boss on the drain plug. Installed a new gasket and filter. Used 6 new pan bolts.. They are very soft bolts so dont overtighten them. Put it all back together. Took a 12 MM bolt and drilled a 3/16 hole in it. Cut it to 1/2 in long, Brazed a 1/4 in pipe coupling on it. I took the same pump I use to suck the oil out of the engine and pumped 5 qts into the tranny.. started the engine for about 5 sec. Put the rest of the fluid in a quart at a time and ran the engine for 5 sec after each quart until I had all 8 qts pumped into it. Removed my adapter and put the plug back in. 2 hrs and Done... No big deal. I notice the shifting seems much smoother now also.. The old fluid looked like Coke. No junk in the filter but was some metal fuzz on the magnets.. 60,000 miles.

The fluid gets very black due to graphite in the friction plates. Doesn't hurt anything, just looks terrible.

Maybe I just debunked another Mercedes idea.. There just aint no reason one cant change the fluid himself..

Nice job! I'm always impressed when a determined DIY'er figures out a way to get the job done. Congratulations! :beerchug:

You Macgyvered that transmission fluid change with class!
:bowrofl:

I believe I read somewhere on the WEB a year or so back that some Euro Audi's are now setup that way - driver cannot pop hood.