I’ve had a problem with jerky shifts. It happens ONLY when the transmission is cold, on the first start of the day. And ONLY 1-2 and 2-3 shifts. In Comfort mode just the 2-3 shifts, of course. When I say “jerky”, I mean near violent snaps when it shifts. Honestly, if I were guessing, it almost feels like the TC lockup is stuck on when it shouldn’t be.

After five minutes or so of driving it goes away, and the car drives perfectly for the rest of the day. If I let the car idle in the driveway for 5-10 minutes it doesn’t happen, or is greatly reduced. With no remote start, though, that’s really just not a good option.

So the other day, as I was doing some other work with DAS, I reset the 1-2 and 2-3 transmission adaptations, and by that I mean I cleared them entirely. Did not drive it afterward until today. Today I took off as normal after a cold start, and to my delight the shifts were so perfectly smooth you couldn’t even feel them. That lasted for about two blocks... then it was back to the jerking shifts, same as before though maybe a little less violent.

I had been thinking I was dealing with a valve body or solenoid problem. Now I’m not so sure, since it is apparently capable of driving just fine even when stone cold. I’m not sure where to begin making adjustments in the adaptations, though. I don’t want to just start changing random things, partly because it’s a complex system, and partly because any change I make I can’t really test until the next day.

So... if someone here really understands what the adaptation values mean and how I should go about trying to adjust them, I’d welcome your input. By the way, this is a 722.6 transmission in an ‘07 S600 with just under 60K miles. I put new Pentosin fluid and a new filter and pan gasket in last spring. The fluid level and quality look good.

 

I agree it sounds to me like the two solenoids are history. I have seen some youtubes where they replace the conductor plate and the solenoids. Sorry to hear your baby is a little sick.

 

Well, gee, that was so very helpful. Thank for the “go Google it”.

As I said... it it obviously CAPABLE of shifting smoothly, since it does so for a short period after the adaptations are cleared using DAS. It also shifts perfectly once the transmission warms up with a few minutes of driving, or even several minutes of idling. And yes, I do have DAS, which I thought I already stated.

What I’m looking for is someone who actually knows something useful that might put me on the right track.

 

Well... there are more than two solenoids, and I’m not inclined to start randomly replacing parts. I did some more diagnostic work this afternoon and a couple of the adaptation values have changed, so we’ll see if it made a difference tomorrow when it’s cold again.

 

Yes, it sounds like hydro-mechanical problems, for example the conductor plate and solenoid(s) could be the problem. The 722.9 7G-Tronic is known for this, and conductor plate replacement at high mileage is not unknown. Is this the same for the 722.6?

Faulty shifting when cold, then smoothing out when warm suggests malfunctioning solenoids.

Faulty shifting after successful readaptation suggests malfunctioning solenoids.

Hard shifting as if the lockup clutch was locked up when it shouldn't be locked, suggests malfunctioning solenoids.

I would start a diagnostic path toward transmission replacement or conductor plate replacement, if that is an option for the 722.6. In other words, suspect the worst until it is proven not to be the case. It's a 13 year old German vehicle, a Mercedes at that, and one that hasn't been driven much.

To the original question: adaption is Mercedes word for the software logic for hydraulic (solenoid) control, given user inputs (pedal position and speed) and vehicle state (speed, engine rpm, trans oil temperature, etc.). Transmission shifting is a complex symphony of valves (solenoids) and clutches, powered by pressurized oil from a pump.

 

Dale:

I know exactly what it is: You have to move to Texas!

Regards from the border with Mexico.... Mark

 

the adaptions get rebuilt after you wipe them... it will change like a dog for at least 20 miles and if nothing worn or broken, will get as good as it thinks it can over the next few hundred miles

there's a few in the UK that get this and can drive about with it connected and adjust each adaption to better optimise changes than the car can on its own.

these are hideous boxes, that change like a joke at the best of times, the fluid needs the right spec (early one uses different fluid to the later ones) and the fluid is usually full of half the clutch material and other metallic wear - this goes round and round ripping up all the seals till the fill times are past the limit the box can adapt to then it either changes badly or under hard use can slip.

Everything inside it wears heavily with v12s needing a rebuild at 50 k miles

 

Still sounds like solenoids. You replaced some or all of the fluid and the filter recently. Sounds like age or some debris has caused an intermittent failure. I would hunt for the best price I could find on OEM or German not Chinese (and I don't mean the box was made in Germany with the part from China) parts. You will have to buy them anyway.

Just cause you think I am stupid doesn't mean that I am not right.

 

You said the 1-2 and 2-3 shifts slammed intermittently. Only 2 of your solenoids are bad. Watch this so you can test and decide. And I am right. Good luck.

 

I don't think you're stupid, and I'm sorry if you got that impression. My first reply was to someone else, and not directed at you -- it looks like you posted while I was typing it. If I ask a question here, I've already done a search for the answer and not come up with what I needed.

Not long after I bought the car, it would go into limp mode once in a while. DAS was calling out an "implausible" speed sensor. I dropped the pan and replaced the conductor plate, filter, and pan gasket. I cleaned the solenoids and checked the O-rings for damage and the coils for resistance and proper operation. I did not do any pressure or leak testing.

The symptom appears only for the first few minutes of driving of the day. @mcypert , it doesn't matter if it's 30 degrees outside or 90... it just warms up a little quicker on a hot day, but you'll still get a few minutes of jerky 1-2 1nd 2-3 shifting. After it smooths out, it's fine until the next day. I've done the TC cold temperature adaptation road test, which made no difference. I had not done the shift adaptation road test, since it required transmission oil temps above 60 C, and this only happens when it's well below that -- but last night I tried that as well. We'll see if that made any difference. I'm not particularly hopeful about it, but it seemed worth a try at least.

Anyway... I thought there was a way to specify some of the fill pressure and timing, but I see now that I did some more poking around that there really isn't. Probably just as well. Looking at how the hydraulics in this thing work, I can see that it could be a solenoid with a problem... or it could be in the valve body... or it could be the new conductor plate... or Lord only knows what else. So... never mind. Forget I asked. I'll figure it out eventually.

 

@DaleB You have a transmission which had a conductor plate replacement, recent oil change, and is shifting non-nominally after electronic remedies (readaptation) are applied. Something is not right in the hydro-mechanical system. This is corrected by replacement of parts. Generally with transmissions, the procedure is to replace the conductor plate (again) or the entire transmission. It's an expensive and time consuming proposition, unfortunately. It's a 13 year old complex German car that doesn't get driven much.

 

I think you have to isolate the variables, so I would do it in a few steps. If you don't want to test the solenoids, then I would first replace just the 1-2 and the 2-3 solenoids, change the filter and fluid (again with Pentosin ATF 134 !!); and drive it. If no joy, then go for a new conductor plate and valve body; and if still no joy it is either a new transmission or call Tommy Torch (just kidding!). Dale, I know this a pain in the tail; but I am willing to bet you a six pack of brew that swapping out those two solenoids with filter and fluid change will do the deal for you. Once you are operational again, it won't feel so bad. These cars are the best in the World. They just need love.

After you resolve, let us know. If I am proven correct, I will tip a beer with you by Zoom to be socially responsible.

 

Here is another very nice guide to doing the valve body, the conductor plate, and the plug. I just checked FCP Euro and they have a kit for about $286 and OEM solenoids are about $318 each and I am betting you can get away with just two.

 

hundreds of threads in every merc forum discuss poor shift quality when cold....

mine has at time been truly offensive in the last year. It was actually far worse after a fluid and filter change. Oddly having read your post, I was thinking about it as I drove off yesterday at 14c ambient, and they were the best its ever managed... must have been having an off day

this is an obvious extra they ALL need when doing a fluid change

 

This video was quite good. I especially liked cleaning the solenoid and the valve with a magnet to get metal shavings out. Dale, I am also betting that 2 of yours are partially clogged. You might be able to save the cost of the part yet. Let us know what you find. My beer bet still stands.

 

the values are unique to the build and wear tear of your box.... it works out how long did it take for the gear changes and within pre described limits, it tweaks the values based on learning over many miles. The idea being if it takes x milliseconds to travel enough to get the desired behaviour (gear changes) and on yours for that gear it took y milliseconds, fill the chamber with more oil to get the job done fast enough that it takes up the slop inside your box and or the lazy speed of the servo till it changes how its should...


7g has a teach in set up - but this suggests not the v12 box? there is a bit about the fill times on later pages.... he rebuilt the box in the end

https://forums.mercedesclub.org.uk/i...ptions.163415/

if its got more wear and or slower actuation than it can cater for within its adaption limits, this is where you can tweak it manually I believe. Pushing it slightly more than the system is designed to manage. And it gets a few more years life. As I said in my first post 1 mile isn't enough to rebuild even the most basic set up on its own.... it needs at least 20 miles for the basic calibration then another few hundred after that to optimise.... and that's on one that's operating within Manu spec.

 

Good description above.

Think about "slack adjustment" in both hydraulic and mechanical brakes. Hydraulic brakes are the standard automotive caliper. The slack adjustment is passive, and shows up by way of more fluid entering into the caliper from the brake fluid reservoir, necessitated by brake pad wear.

Mechanical brakes are standard on tractor-trailers - i.e. drum brakes. They are pneumatically actuated, however there is a mechanical "ratchet" device in the system called a slack adjuster. It ratchets as brake linings wear over time, so the pneumatic actuator travel and brake pedal travel remain within specifications.

A transmission is no different. The solenoids are valves to allow hydraulic flow and pressure into a chamber which pressurizes a brake. The brake in this case is a wet clutch. Clutches in an automatic transmission are either plate-type, drum-type, or band-type. They are actuated via pressure, which again is controlled by the solenoids. Non-nominal shifting happens when the clutch components, or hydraulic system are non-nominal. Transmissions are choreographed collections of valves, and time (timing) is an important factor. Slow, lazy shifts mean burned up clutches and burned oil from slippage and heat buildup. So things need to happen quickly, according to a specified time (measured in milliseconds). Debris in solenoids can change performance on the order of milliseconds.

Harsh, clunky shifts can happen when a solenoid at first does not open (or close) properly, because of wear or debris. When the solenoid finally achieves its function, the shift happens too late, or too suddenly, resulting in a harsh or clunky shift. Harsh and clunky shifts can also be caused by friction material wear on the clutch surfaces.

It's helpful when thinking about transmissions to remember that clutch = brake. Each of us has four dry plate clutches at the corners of our vehicles, to wit: the brake pad and rotor.

To @DaleB it seems like a hydraulic system repair or rebuild is needed, at minimum. Next would be conductor plate replacement (again), followed by transmission rebuild or replacement.

 

This whole discussion seems to be intense on "problem thinking" - frankly with 722.6 at this mileage (let's put the age aside for the moment) - either (a) let your S600 warm up for 5 minutes to minimize the "problem" -or - (b) research for someone who has had the problem and actually solved their problem...

https://mbworld.org/forums/clk55-amg...-6-solved.html

 

Thanks for the input. Option A is simply not an acceptable solution for me. With no remote start, I'm not going to sit there in the driveway idling for 5-10 minutes when I want to drive the car. And just putting up with the shifts the way they are is also not a good option, in my opinion. Given the jerks that often occur in the 1-2 and 2-3 shifts, it can't possibly be doing anything good to the transmission internals.

Option B would be nice, if I could find someone who actually had the same problem, and actually fixed it, and actually posted what that fix was. The thread you included in your post was informative, but I'm not experiencing delayed shifts or shift flare. I've done quite a bit of searching here and on other forums, since the 722.6 is also known by other names in other brands of cars. The Mopar guys seem to experience harsh shifting when cold quite often... and their consensus seems to be to live with it. Maybe that's acceptable for some guy with a Charger or whatever, but I want to actually find and fix the problem.

I will say this... My understanding of the function of the solenoids was very incomplete. Now that I have a much better picture of how they operate, I think my next step will be to drop the pan and valve body, pull the solenoids, and thoroughly clean and test each of them along with checking the valves for wear. I have some doubts that this would be a valve issue, though. First, the transmission doesn't have many miles on it -- at 60K it should be barely broken in. I'll temper that by saying that the original owner never had the transmission fluid changed in the 47K miles he drove it, and when I got the car the fluid was pretty toasty and a little low. Second, this was not a gradual issue. It went from "everything's fine" to "what the hell was that?" rather suddenly, leading me to suspect it may be some debris or crud that needs to be cleaned out.

It will be a couple of weeks before I can get the car up and drop the pan. I've got a couple gallons of ATF on hand, but I'll need to order the drain plug gasket and I may as well replace the pan gasket and filter as long as I'm in there -- they're cheap. I'll post results after I've had a chance to do a little more exploration.

 

a TC, a set of solenoids, and an electro plate is "normal servicing on a Mercedes"

(and if of a certain age, so too is a non-combined trans fluid and water circuit radiator many were made with)

a 50k mile rebuild with new o rings and I guess new clutch plates normal on a V12 is the throttle pedal was ever used

 

Dale, I think you have correctly analyzed it and your plan over the next few weeks is good. I would suggest that magnet procedure as part of the solenoid cleaning you plan to do since I also agree the problem is debris. If you save those 1-2 and 2-3 solenoids with a good cleaning instead of having to replace them, I suppose I owe you that beer.

Let us know how it goes. Best wishes,

 

Dude, if I can get the last few little kinks worked out of this car, I'll buy beer for everyone. It's been considerably more of a "project car" than I ever dreamed it would be. At least the stuff I have fixed stays fixed... but troubleshooting some of these issues can get to be a real head-scratcher. You don't even want to hear about my heat issue right now...

 

Let me guess...... Karnak the Magnificent says heater control valve at the firewall..... And let me guess, you already replaced it.. Betting that little pieces of plastic are stuck in the hoses at the valve. How close am I?

 

Oh, don't I just wish it were that straightforward! Suspected the valve was bad, replaced it. The old one snapped while removing it, no big deal, got the pieces out. It was definitely bad, or at least the rack & pinion that moves the valve was jammed with some debris. The new one went in without issues. STILL no heat in the front; the rear works perfectly. I can hook up the laptop and watch the temperature sensors and see that it KNOWS the inside of the car is well below the set temperature, and it KNOWS the vents are blowing cool air. If I go into the front SAM actuations I can manually cycle the valve OFF/ON and the air will get hot, then cold, depending on the position of the valve... so the new valve definitely is working. So, everything appears to work... except it doesn't actually warm up the front seats, so one's toes get pretty cold on a long drive in cold weather.

Now, the weird part is, the valve operation seems to me to be bass-ackwards. If I set the valve to OFF in DAS, the air from the front vents gets warm. If I set it to ON, the air cools. I don't know if that's wrong or just some half-baked German way of looking at things, since I have no working car to compare it to and the diagnostics don't say anything about it (I don't think). I guess I didn't read all the help pages, I may need to do that. Anyway, it's almost as if the thing is wired backwards. I'm contemplating swapping the wires to Y19/2 (the AC water valve) just to see if that fixes the problem. How would it have gotten that way? I've no clue. I suppose it's possible the front SAM firmware could be incorrect for this vehicle or something. I know I haven't touched the wiring or the SAM, other than to clean and re-seat the plugs once. The plug for the valve can only be installed one way. It's a mystery.

Edit: I just thought of one thing that could be wrong. It's entirely possible that the valve simply has the motor leads reversed. I've seen how these things are built; I took the old one apart. Dead simple motor with a worm gear that drives a large spur gear, coupled to a small inion gear that drives a rack to pull the valve slider up and down to control water flow. If the motor is installed rotated 180 degrees from where it should be, it will run opposite of its commanded movement. Since it's an open-loop system, the SAM would have no idea that this was happening. I'll swap the wires tonight and see if that fixes it.

 

3 pipes ?

and what's the rack bit..... swapped my rear the other day, the one behind the right front wheel on RHD car (allegedly the same component) there's is no rack element? two solenoids and a pump.... can you put the pipes round the wrong way ???