OK, so I bought a positively gorgeous blue (IMHO) like new M111 powered 2002 C230 Sport Coup sight unseen with just
35K miles, California car, no rust, and Carfax maint. going back to 2005 when the 2nd and most recent owner purchased.
Always repaired by dealers or German car specialty mechanics with a brand new set of $1000 Conti tires.
I figured it was a no brainer.

It was one of just a few of these M111powered available anywhere but also happened to be within 30 miles of the airport
that our little local airport flies directly into.
SOOO....I get there, yes, it's beautiful and like new. I've already bought and paid for it.
I go to drive it back home 400+ miles and CLUNK! upshift 1 to 2 CLUNK! downshift 2 to 1
Crap. So I switched into W mode and drove it home, skipping 1 altogether, no issues. Only 1 to 2 and 2 to 1.
Along the way I scanned it with my iCarsoft, no errors in the TCU. (and later with my new Launch Eilte 2.0 same result)

So #1 I get a fluid sample and send it to Blackstone, level was a bit high, thought maybe thats all it was but then....
#2 I pull the bits apart that allow to me to read the word on top of the radiator I was
dreading to read. VALEO !!!
Arrgh. So, crap. Sample comes back high in Sodium which apparently means there is anti freeeze in the trans fluid.
Fluid actually looked good transparent and red. It had been changed 4K miles ago, 8 years ago!
Seriously. I have the name of the shop. I'm tempted to call them. Not sure what I'd ask though?
So I ordered a radiator, 12 quarts of ATF134, a conductor plate, filter, gasket, and 'pilot bushing' (the part with the orings).
I also checked the TCU under the kick panel, all good, same under the car, no oil in the loom.
This car is so clean literally. And not a spec of rust. Most of the factory labels are still attached. Looks like it was never driven in the rain...ok, anyway.

I pulled the radiator, which unfortuntely on a Kompressor means removing the front bumper
and intercooler.
I got it wrestled it out, and then I started on the transmission.
I dropped the pan, drained out the fluid, and while cleaning up today discovered the pan was very rough inside
and some of the paint was gone here and there. What the heck?
My other 260K mile vehicle (Same year model and color BTW, I like it so much I bought another!)
the inside of the pan is very smooth even though it's 1st service didn't occur until 120K miles, since at that time
Mercedes falsely claimed it was "sealed for life" a bold faced lie! I did a full flush twice and now every 40K I do a drop and fill. 260k miles and never a problem except the shift module
But the point is, no pitting, missing paint and smooth on the old car.. I just had it off a 1 or 2 thousand miles ago due to a leak. Perfect.

I just now ordered a pan from Napa, I think it's Dorman. It's supposed to be here Weds. I hope it's as good as MB?
But I get it quicky.
Next step is pulling the valve body, and while I have a genuine OEM Kostal conductor plate standing by, I'm begining to wonder if there's anything else I should do? Should I replace any selenoids? I can't seem to find them for sale, and if I did, how much do they cost? I'd hate to go through all this and it still doesn't shift correcty.
Is there any one specific selenoid that controls 1 to 2? All the other gears shift fine.
I really DON'T want to have to take the valve body apart, thats beyond my skill level.
I'm sure I could really mess things up if I do that, but should I? I saw a video about that, and it mentions these tiny filters and what not.
I hope the trans filter did it's job and caught those bits of paint. Like i said no code, and all other gears are Ok.

So I'm concerned about a couple things. I've read about the CP bolts snapping off on removal.
Seriously? Is that something I need to worry about? How can I avoid it. Pan bolts were WAAAY over tightened.
Took an inodinate amount of force to remove.
And how much does the valve body weigh out of curiousity?
Is Radiator, filter, conductor plate, and full transmisson flush enough?
And then I see i need to clear the adaptations which the Launch claims to be able to do, and
I found a document outlining the process driving below 2400 rpm and shifting the gears etc.
then parking for 10 minutes with the engine running. Is this correct?
Please advise!!!

PS. I can't believe that for a vehicle with such an extensive maint. history,
no one apparently advised the owner to replace the Valeo radiator.It was obviously loved and charished,
garaged. Sad. And yes, buyer beware, but dealer never mentioned this issue. Salesman said
it drove "perfect" no issues whatsoever!! When we took it out for a drive when I got there, he says
Well you know, it a used car! Uh....not what you said before.
Kinda pisses me off, but Caveat Emptor. Otherwise the car despite being 23 years old, is like new.
It doesn't even have a door ding or a single scratch! I think the dealer likely touched up some things.
Well also defrost is stuck. Clicks for 5 minutes each time i get in the car. Another issue not mentioned. Oh well.
Hmmmm....thats a hellish job to fix, but 1st the issues at hand.

 

congrats on your fine acquisition

Don't replace the solenoids but do clean up their individual strainer screens.

Solenoids control clutch packs in combination. WIS will show you which solenoids work 1 & 2 gears.

Your rear calipers are likely rusted solid on the inside... new units.

Front control arm bushings likely chewing gum. This will help restore good steering

 

Calipers? No issues with calipers. I said CP as in Conductor plate.
The bolts I was concerned about are in the conductor plate. I will find out today.
New pan comes tomorrow.
Screens?
Something to do with the selenoids?
You don't mean inside the valve body do you?
I guess I'll see when I get them out.
Control arms? Not seeing an issue there. I will be looking closer when reinstalling the bumper.

 

solenoids + conductor

clean the solenoid screens ss you replace conductor.

I mentioned your rear calipers because at that age they are guaranteed to need care.
Just saying check rears are not tight or spongy.

 

I saw a video where the screens were mentioned. I didnt get a good look at them,
but it was stated it was best to remove them from inside the valve body. I"m
not at the stage yet where I would feel comfortable taking the valve body apart.

On another note, I got the valve body out of the car yesterday.
I make an interesting discovery. The conductor plate has already been changed and fairly
recently. The date code was 11/19. The new one I just purchased is 5/24 so sitting on a shelf for a year.
It's the genuine article, LK stamped into the plastic. So, that means, this was already a known issue and
might explain why in 6 years the vehicle was only driven ~2000 miles.
I'm feeling a little lost at this point, if the fluid was flushed as it appears to have been,
and the conductor plate was replaced, then I'm just repeating whats already been done in just the last
couple thousand miles. And my result is likely to be the same.
So, my next step would be something to do with the valve body or selenoids or both?
I've immersed myself in youtube videos of people rebuilding the valve body. Sonnix bit and pices.
I'd really just prefer to hire someone who is competant in this area to service the valve body,
should it need it. Well at least unlike the other mechanics who've serviced this
time capsule before, at least I'm getting rid of the cause of the problem, the stinking
radiator. But I'm feeling a bit down about the whole thing.
What's the next step? I'd don't cheriish going through the process of draining the fluid and
and dropping the valve body again. I'd like to "shotgun" it, and be done. As in replace anything that
has to do with 1 to 2 shifts. The 4 to 5 is fine so I guess it's not a selenoid?
What now? What else should I look at? I know jack about transmissions. Arrgh.

 

I dont have any experience with that transmission so was looking thru the manual. I like to see if there are any bulletins on specific issues.

I came across something interesting about harsh engagement, caught my eye because it mentions glycol contamination of the transmission fluid, vehicle produced before 2003 and Valeo radiator.

Heres the link to that page, I wont cut and paste the entire thing: https://charm.li/Mercedes%20Benz/200...zzing%20Noise/

 

Yes, I'm replacing the radiator as well.
I'm going to replace some valve body parts with a sonnex kit which is specifically for that problem. Servicing the valve body is my last hope for a DIY repair.