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722.6 Slow shifting: fixed today by replacing trans conductor plate

15K views 26 replies 6 participants last post by  Dave2302 
#1 · (Edited)
The silver S430 has been getting a lot of TLC from yours truly. This stuff is fun. :)

The transmission's shifting felt kinda sluggish. It's never failed to shift, and it's not in limp-home mode, but the shifts would feel just slightly klunky--no banging noises, just a feel--and it was starting to get very gradually more mushy, if you will. There were no codes. It'd probably be fine for another 10,000 miles, but I just don't like sloppiness on a Benz. Better to deal with it sooner, when I can take my time and do it right.

Some Googling and STFF'ing said something about the speed sensor typically causing this, and the way to deal with one of those on the 722.6 transmission is replacing the conductor plate with a new one. Since I already had a plate handy, I thought, might as well try an experiment.

Sure enough, it worked. Shifts did firm up considerably, which I consider a good thing. The "klunky" feeling is pretty much gone. I had done the transmission fluid and filter exchange (the full 14 liter version) about 5,000 miles ago, and apparently dropping the tranny pan really does result in a loss of nearly exactly 4L of fluid. Four more liters of the good stuff took care of things. Also replaced that made-in-Taiwan Meyle filter with a genuine M-B filter, as well as a new trans electric connector (also M-B brand). Hey, those have to come out anyway, so might as well, right?

The job took me about 5 hours, since it was my first one, and as usual, I'm doing it on the street, i. e. no lift. Actually, since my buddy's borrowing my jack, I did it with the car's front end up on a pair of Rhino Ramps. :) Yes, it can be done. It's a little awkward getting the valve body back in, especially if you have long arms, but it's certainly doable. Next time, it'll probably take me about 2 hours since I now have a better idea of how to do it.

While I was at it, I checked the resistance of the solenoids. All of 'em are right within spec; matter of fact, they're at dead-center of the acceptable range.

Miles on the car are 143K. Tonight's test drive was a pleasure. Well, driving that car always has been, and now it's even more so.
 
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#2 ·
The w220 generation of the 722.6 is suppose to be the one with the better internals. I actually have internals of 01 s55 transmission in my storage for my w140 along with a lsd. I have been told my 722.6 was bad 50,000miles ago but knock on wood the tranny is still good it only leaks a quart in a month. Did you do the shift lock linkage? Its easier to do with the conductor off. Also it would have been a perfect time to do the filters in the valve body and replace the springs. I have done the conductor on a w210 and w202 it took me 4-5 hours the first time and about 1-2 at the shop on a lift with air tools and a buddy. The valve body is sensitive to dirt and small particles.
 
#3 · (Edited)
No, I didn't do the shift lock linkage; didn't know that needed to be done. I did notice there are screen filters under some of the solenoids; were you referring to those? If so, I did take those out and look at 'em, and they looked clean. Never occurred to me to replace the springs. I've never taken a valve body apart on *any* transmission, so this would be a new adventure.

I'll remember these tips for the next one, though. I'm guessing the S600 will need it next, possibly also the E320 CDI project car.

Much care was taken to make sure the transmission didn't get any dirt on it. Soon as I got that valve body out of there, it went straight inside, on a clean, lint-free environment, for the work.

Might be worth it to get a spare 722.6 transmission just to learn how to take certain things apart on it and put 'em back together, without risking messing up a daily driver. That will be a little while until I can get a garage, though.
 
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#4 ·
Yes i was refering to the screens on the solenoids. The w220 has the reliable 722.6 transmission. It recieved the "updated valve body". There is a seal that goes on the shifter linkage and once that goes bad its a pita to replace. The pressure springs sometimes snaps or atleast on the pre 2000 model transmission it was really common. I am going to do the valve body in my w140 when i get days off from work so i can barrow the car lift might even get the internals replaced with the s55 trans i have in storage. I have a really bad habit of buying parts and keeping them in storage. For example in my storage i have brand new leather set, a lorinser body kit, and 18" monoblocks not to mention s600 door panels, b pillars, steering wheel and wood set all for my w140.
 
#5 ·
Currently on a road trip. My car's driving great. Even after a 16-hour drive, I didn't get tired; W220's are wonderful for cruising long distances. I really do see why people buy these cars.

However, I did notice that the computer's fuel mileage is now...um...a bit off. It's showing between 28 and 29 mpg fairly consistently. However, my handheld calculator tells a different story. After 564 miles, I filled up with just under 23 gallons, which I found interesting given that I wasn't on empty yet. Stated fuel capacity of a 2003 S430 is 23.2 gallons. The fuel gauge was just a little ways into the orange "R" region, so I might've been getting a bit of--shall we say--"country" fuel dispensing readings. Alternately, this pump might have a different cutoff calibration (gasoline vapor pressure) than others I've seen.

Either way, it's a far cry from the 28-to-29 mpg that I was seeing. I recall the car computer's numbers being much closer to hand-calculated values in the past.

There's a Costco on the way home. I'll try filling up there and seeing what we get. Will update this in the other thread about W220 fuel usage accuracy. Am keeping all fuel receipts for this purpose.
 
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#6 ·
The fuel consumption gauge was spot on with my s65. I drove non stop from oregan to california and i was shocked that i averaged 23mpg. Then again with my w140 i averaged 28mpg on the same road before. I was extremely tired on ride back to california because we took a greyhound for 1100miles non stop with no sleep and bought the s65 and drove back to California non stop for another 1100miles. I was knocked out cold when i got home. The only down side is you get sleepy with the w220 esspecially the 04-06 models which have no aux port (i have retrofitted a fm transmitter connected through the factory bluetooth) audio sounds clear as a CD.

But it looks like you wont have aux issues since you have an 03. By the way 06 model w220 did not have tape players either but mp3 dvd playback was supported.

Have a safe trip
 
#7 ·
Hi all, I came here to start a new thread about my 2005 S600's 722.6 transmission, but found this recent one so I thought I'd try tacking on.
Bought this car a couple months ago sight-unseen from a dealer on Ebay, nothing mentioned in the ad about the trans. Got the car (it was delivered), go for a spin, and I think, "Man, this transmission's slipping." For sure in 1st gear, maybe others, and the shifts aren't at all what you'd call crisp.
Read up on the forums, did the adaptive reset thing, and that helped the 2-3, 3-4, etc, shifts, but it still seems to be slipping starting from a stop. As in the RPMs go up to about 1500 just to get the car moving, even closer to 2000. At idle on a level road it'll hardly pull itself.
Then I remembered that my 2000 Jaguar XJR had "a Mercedes Benz transmission", did a little research, and lo and behold it was the 722.6. I absolutely LOVED that transmission, best automatic I've ever had (out of maybe 20 cars I've bought over my life). Okay, same transmission, so there's definitely something not right with it. I'd read about the 13-pin connector causing problems, so I bought one of those, some fluid, and a new filter, figuring I'd just swap the connector out and see if that helped.
But then I hooked up my STAR system to see if I could learn anything about what was going on, and wow, a TON of codes. I had read up on the conductor plate, read some how-to's, and watched some videos, so I feel comfortable I could replace that if necessary. I'll list some of the codes below, but what I'm trying to figure out is if people think just the connector would fix all these, or if it's more likely the conductor plate. I don't want to have to drop the pan twice.
There's a full 3 pages of codes in the error log:
P2100 - The internal electrical check of component Y3/6y3 (1-2 and 4-5 shift solenoid valve) has failed.
P2101 - " " " " " " " " " " " has a short circuit to ground.
P2102 & 2103 - same messages for the 2-3 shift solenoid.
P2104 & 2105 for the 3-4 solenoid.
P2106 - internal electrical check of torque converter lockup PWM solenoid valve has failed.
P2107 & 2108 - same for the modulating pressure control solenoid and shift pressure control solenoid.

And some others. Those electrical-type codes made me think that it might just be the 13-pin connector, but then we get to:
P2502 - The gear is implausible or the transmission is slipping. Then there's P2560 through 2564, those same words, but for each gear.
P2507 & 08 - Engine overspeed Y3/6n2 & 3 (speed sensor 2 / 3)
P2602 - The voltage supply of the valves is faulty. & 2603 for the speed sensors.
And from what I've read of speed sensor errors, that points to the conductor plate.

So what do you guys think, buy a conductor plate and just do it all at once?
What else should I do while I'm in there?
Should I do the shift linkage seal mentioned above, even if it doesn't appear to be leaking when I get under there?
Should I buy any of the parts that Sonnax makes to deal with worn bores in the valve body? The car has 117k on it.
Thanks,
Mike
 
#8 · (Edited)
Hi,

Sorry to sound like "The Prophet of Doom" here, BUT, here's what I'd do, (being a Semi retired Auto Trans Specialist) .........

Make sure Oil Level is correct first.

Clear out all Faults and Events, drive the Car for a few minutes / days and see what comes back, they just may be old codes caused by someone working on the Car before :wink

If you keep getting Ratio Errors, Speed Implausible, Slipping etc then get a known good used Tranny and Converter, or get Rebuilt Units fitted by a good Transmission Specialist :wink

In my experience you will most likely be wasting your time and money fitting Parts to this Transmission ............

Not always, but 99% of the time :wink

HTH

Cheers Dave
 
#9 ·
It would be interesting to do the resistance and actuation tests on those solenoids. If enough of them are bad, then Dave's probably right in his suggestion of a good used or rebuilt transmission. One of those solenoids is US $300. The others are typically around $65 to $85. All of mine checked out OK, so the conductor plate replacement made sense in my case.
 
#10 ·
@Theinkdon: Those codes you saw...since you have STAR, were the transmission codes "stored" or "current"?
 
#11 ·
Dave,

Well that's certainly not what I wanted to hear! I appreciate your advice, but for a couple hundred bucks for a conductor plate I might just have to try it. If nothing else I'd have a new plate to stick in a known-good used trans. After all I've read about the 13-pin connector and the conductor plate fixing people's problems, I thought surely the diagnosis would be to try that. I'll post back in a couple weeks when I'm done and give you the opportunity to say, "Told ya so!" ��

Cowboy: good idea. Once I get the plate out I'll test the solenoids. Resistance checks I can do easily enough, but I don't know yet how to do "the actuation tests." I'm sure it's here on the forums. Maybe the $300 one is good and I only need to replace a couple $75 ones.
I don't know if the codes were stored or current, because my laptop's battery was dying so I quickly saved the error log (that's what I posted from last night), and looking at it again, it doesn't designate which. It was my first time using STAR, and I was actually troubleshooting something else when I came across the transmission menu and took a peek at that. I'll do what Dave said and clear the codes this weekend and see what comes back.

Thanks for your help, guys!
Mike
 
#14 ·
Try this before a new transmission.
Thanks for that. Before I saw your post I ordered a Mercedes branded one from Amazon for 127.94 with free shipping. Will put that in next weekend and report back.

Also ordered (from Rock Auto) the Sonnax Master Overlap Control Valve Sleeve Kit - 68942-05K
based on some things I read. I don't think it will help my specific problem, but with 117k on the transmission they may help shift quality, and I'm going to have the valve body out anyway. 36.79 plus 6.99 2 to 3 day Fedex. Every place else wants about $67 for that kit.
 
#15 · (Edited)
Hi,

Quote

Dave,

Well that's certainly not what I wanted to hear! I appreciate your advice, but for a couple hundred bucks for a conductor plate I might just have to try it. I thought surely the diagnosis would be to try that.


No, sorry but I disagree .........

That is "chuck parts at it until it's fixed", and IMHO that seldom ends well, and always costs far more than proper diagnosis. It gets very very expensive very quickly :wink
Proper diagnosis is, first clear all codes, then see what comes back..........
Then, check all 'relevant to fault codes(s)' resistances at the external Trans Connector, and if faulty, remove valve block and check those components ............. So far this has cost nothing ..............
What if you replace all these parts, and then the same codes are there ??
"Oooooops, I've replaced the Conductor, the Solenoids, Plug, Oil and Filter, and it's still the same, oh dear, must be the Wiring to TCU or TCU itself" ..............
What about the 'slipping', that indicates Worn Clutches or Torque Converter breaking up internally.
If you pull the plug from the Trans, it should still Drive and Reverse without slipping :wink

See what I mean ?? :wink

Proper Diagnosis is eliminating everything else at minimal cost until you know exactly what is the faulty component :wink

I'll post back in a couple weeks when I'm done and give you the opportunity to say, "Told ya so!" ��

I would never do that :devil
I'll be happy if you tell me it was the Conductor Plate, but I'll be very surprised if it is just that, and you will be in the elite 1% "dead lucky" bracket, and on that day I will suggest you go buy a Lottery Ticket :wink

I'll do what Dave said and clear the codes this weekend and see what comes back.

Yes, do that and I can advise you further on what action I'd take, if your Car was in my Workshop :wink

Thanks for your help, guys!
Mike


No Proberlermo :wink

HTH

Cheers Dave
 
#19 ·
What's the "sheepish look" emoticon?

So all those fault codes I posted? That was the "Full list of fault codes and events" from DAS, more than halfway down the ETC screen. Boy do I feel dumb. "Fault Codes" is the second from the top. http://www.benzworld.org/forums/images/BenzWorld2/icons/post_face_embarrassed.png I guess I was so fixated on it being an electrical problem that all those electrical-type codes made sense to me.

That is "chuck parts at it until it's fixed", and IMHO that seldom ends well, and always costs far more than proper diagnosis.
Proper diagnosis is, first clear all codes, then see what comes back.
What about the 'slipping', that indicates Worn Clutches or Torque Converter breaking up internally.
If you pull the plug from the Trans, it should still Drive and Reverse without slipping.
So Dave (or anyone): I went to clear the fault codes yesterday, but there were none. I thought maybe I'd cleared them the other day, but maybe there never were any. So I drove it to work today, about 12 miles each way, and NO FAULT CODES are set. I know that's not a very long time/distance, but three Events did come back, but I'm guessing they're not related to the driveability issues:
P2314 - "One or more messages from control unit N93 (Central gateway control unit) are not available on the CAN bus. (CAN timeout fault.)"
P2315 - same words, but for A1, Instrument cluster.
P2316 - same words, but for N19, Air conditioning control module.

So let me get back to basics, here's what the trans is doing:
Barely pulls itself in Drive when idling. *barely*. I had this same trans in a Jaguar XJR and that thing would idle up a pretty good grade.
Ease into the throttle and it's 1500 to 2000 RPM before it really starts to move. This thing is "slipping", no doubt in my mind, and it's embarrassing driving around parking lots because I'm having to rev the engine pretty high just to get it to go. I think it does this in both Sport mode and Comfort mode, which if I'm not mistaken, just starts you out in 2nd. At least when I got the car it was in Comfort mode and I attributed the "feel" of slipping to that, but went to Sport mode and same thing.
After getting into 3rd and higher it seems to act normally, no hesitation between shifts, no crunching/grinding/rumbling, no apparent "slipping", and the tach seems to agree with road speed.
I've tried to feel for converter lockup, but can't say I've felt it, even though part of my trips today were on highways at 65+.
At the Transmission Control Unit (or ETC as DAS calls it) there's NO indication of trans fluid wicking up the wires.

Now let me add something I forgot initially:
Sometimes when putting into Drive or Reverse, the trans doesn't engage. It happened this morning after I dropped my daughter at summer camp: parked, car off, 5 minutes later start it, select D, and nothing, it was as if the car were in neutral. Slipped the selector to N, back to D, and it engaged.
The same thing has happened in Reverse, once when the car was pointing downhill and I was trying to back up, but it literally rolled forward, no kind of engagement or drag. Put in P, back to R, and all was good.

Early on I bought this dipstick:
https://www.amazon.com/gp/product/B...ZT72189Z6HZQY8KS&pd_rd_w=kymoF&pd_rd_wg=2nk3L
and I don't remember exactly, but I think the fluid level was a bit more than half. After a drive, so trans was at operating temp, level ground, in Park. In hindsight, maybe I'm misreading that, because I think the upper mark is for 80C, while the lower mark is for "cold", is that about right? I was reading it like an oil dipstick: "between the marks is okay."

So tomorrow I'll check that again and top it up if needed (with Pentosin).
Assuming that doesn't help, what next?
Do these symptoms (especially the no-go when in gear) point to the torque converter?
I'd still like to drop the pan and see if there's anything in there; that would be a sure sign. I have the $12 electrical plug, so I'll replace that while I'm under there.

If it's not the TC, how likely is it I'd be successful "rebuilding" the trans? I've rebuilt 3 engines, done some heads, cams, timing belts, differentials, etc. I've got all the normal kinds of tools, including torque wrenches and gear pullers.
Or should I just get a rebuilt or junkyard one, which would be quicker.

Thanks again,
Mike
 
#16 ·
Just got back from the road trip. 1,600 miles later, I can now report for sure that the new conductor plate *did* fix my issues. The transmission shifted very well the entire time, and it feels good 'n' solid. Matter of fact, the entire car feels solid. I guess that's what happens when one actually fixes issues on his car. :)

After 12.5 hours on the road, including a stop for a late lunch, I don't even feel tired...just a little hungry. A bowl of Shredded Wheat should fix that nicely. Got through telling the neighbor's son about how the car behaved on this trip (he's home from college), and that's how he describes his Dad's 2012 C300--silky smooth. Benzes apparently just cruise...and cruise...and cruise.

So, apparently I should buy a lottery ticket. :-D
 
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#17 ·
Just got back from the road trip. 1,600 miles later, I can now report for sure that the new conductor plate *did* fix my issues. The transmission shifted very well the entire time, and it feels good 'n' solid. Matter of fact, the entire car feels solid. I guess that's what happens when one actually fixes issues on his car. :)

That's great news, and isn't it a nice feeling when you've ironed out all the issues and got on top of the Car :wink



So, apparently I should buy a lottery ticket. :-D

Ahhhhh, not really !!

Your Trans was only given "Routine Maintenance", it didn't have a ton of Codes, or Slipping when you started :wink
TBH, I would think in your specific case, that the new Oil Filter and fresh Oil will have made the biggest difference to its performance :wink

Cheers Dave
 
#18 ·
Normally I would agree with you, but I had also done the oil and filter exchange (the 14L version) about 5,000 miles ago, so it's pretty much all new fluid in there. But you are right in that there were no transmission codes showing up. Fundamentally, my trans was in pretty good shape when I got the car, and that may not be the case with Theinkdon's situation. I hope it is, of course, but Mr. Murphy has an interesting way of making his presence known....

Discovered another little issue, though; the AIRmatic pump is definitely struggling. I could hear it on the trip; it sounds like it's knocking (bop-bop-bop-bop, in rapid succession). It takes *forever* to get the car to rise up those 2 cm or so when I hit the Raise button. This is probably because when I got the car, the right front AIRmatic strut was definitely leaking. This was one of those "Stevie Wonder could see the exoxy seal had failed" kind of situations. I figured then the pump was starting to go from overuse. That's also partly why I got the car for what I got it for. So, looks like I'm replacing an AIRmatic pump, and fortunately, I happen to have a new one handy. That part will go in another thread.
 
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#24 ·
Good read, thanks for that. Some of the posts were talking about (C)omfort mode starting you off in 2nd gear, which I totally get. My wife's Volvo XC90 in Wet mode (2nd gear starts) feels about like this car, but probably not quite as slippy. And my XJR, even in Comfort mode, didn't feel like this car does in Sport mode.

But what gets me is, aside from just being in Sport mode and "assuming" you're in first gear, when I've manually SELECTED 1st gear, and the display shows "1S", it 1) hardly pulls itself, and 2) will get to almost 2000 RPM before it really feels like the gear is engaged and it's "pulling".

Another data point to consider: I've NEVER been able to spin the tires with this car (yes, ESP off). Not that I've tried a lot, but my boss had an '04 S-Class with the same twin-turbo V12 and he talks about chirping the tires in the parking garage just trying to take off, or chirping on the 1-2 and 2-3 shifts, or "breaking loose" at highway speeds. So today after I topped up the trans fluid, I went to an unused road in my subdivision and tried a couple times to brake-torque and spin the tires, level dry asphalt, ESP off. Just a bit of a squeal, like a squeegee makes on glass, but certainly wasn't spinning the tires. Don't get me wrong, it took off like a bat out of hell, way faster than the 370HP Jaguar did, but nothing like the Youtube videos I've seen where guys are smoking the tires at will.
The Check Engine light is not on, and there were no motor codes yesterday when I checked, so what am I missing? Do I need to go to Dyno mode? (Btw, I'm 53 years old and don't go around spinning tires, but if I *should* be able to in this car but can't, does that say anything about the trans? And what about peak RPM with the brakes applied? I didn't note what it was, but would that indicate anything about the converter? Other than "you're going to need a new one if you keep doing that!")
 
#25 · (Edited)
Hi,

:laugh , I'm 55 years old and DO light 'em up at times :wink

I have W220 and W203 with 722.6 and both cars do creep slowly on flat ground.

The Supercharged Jaguars with 722.6 drive pretty much the same (Trans Wise) as the Mercedes, just slightly different Shift Points Programmed into TCU :wink

They also suffer from all the usual 722.6 problems, which is no surprise really as the Trannys are Identical :wink
Interesting at that time that Jaguar felt ZF couldn't build a trans to cope with the S/C Jag's Torque :laugh

Mind, they still can't, Audi and BMW (ZF Trans), they are regular visitors with Trannys gone "Bang" :rolleyes:
And when they go, boy are they "lunched", busted sun shells, drums, gear sets etc etc :big laugh:

Cheers Dave
 
#26 ·
Perhaps Dave can step back in and tell us if there is an RPM test for the torque converter on the W220. On the Porsche 928 (and other cars), there is a test where you stand on the brakes and floor the throttle, and see what RPM is developed. (Yes, I know that the computer usually doesn't like for you to do that on the W220.)

Years ago, I was tuning an Olds Cutlass and discovered that I could floor the throttle, and without lifting my foot, could make a right-angle turn and smoothly drive out of the parking lot. The V-8 engine was running perfectly - turned out that the torque converter sprag clutch had failed.
 
#27 · (Edited)
Hi,

Wally is correct, you can't really get an accurate stall figure for the MB due to the Electronics stepping in.

It's irrelevant here anyway.

If the Converter is breaking up, then the Trans will have some form of contamination / wear, and Vice Versa.

This is why a decent Trans Specialist will never change one without the other, unless of course the Converter has a cracked weld on a foot or some such, but even then they will be Extremely Specific on what exactly is covered by any Warranty they offer :wink

It just isn't good practice, and usually comes back to bite your @ss :wink

If I could drive this car I could tell him exactly what is wrong but this is years of Transmission Experience, and a "feel" thing.
No amount of Videos, Fault Descriptions etc etc can make up for "Seat of the Pants and Under the Right Foot" senses :wink

But, from the "it almost gets to 2000 rpm to pull away in 1st or 2nd Gear", (assuming of course that it is actually in 1st / 2nd Gear, and not stuck in 3rd or 4th), it is a 99% certainty that the Trans and Converter needs replacing. And if it is stuck in 3rd upwards, with "No Codes and display indicating 1st / 2nd", then it is likely a complex internal fault beyond DIY Capabilities / Equipment and Cost Effectiveness (LOL is Effectiveness even a proper word) :grin.

The most economic solution for a DIY guy is Good Used :wink

Cheers Dave
 
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