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2003, W203 (C240)
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Discussion Starter · #1 ·
Also, you may have the transmission trouble codes in the module that need to be erased. You'd need the MBstar tool to clean the error codes and reset the adaptations. The tool will also help you check the transmission fluid level since it's very sensitive to the temperature.
Hello everybody,

it's maybe late, but i also have some issues with the transmission. The shifting of a C 240 (W203, year 2003) sometimes isn't fine. It has the 722.6 tran.
I also plan to rebuild the transmission.
There is a question i can't find a clear answer for it.
If i replace the conductor plate, will the TCU accept it?
You write here, i have to use the StarDiag to reset the adaptations.
You mean by "resetting the adaptation" this procedure (Reset Transmission Adaptive Shifting - How to Programming Instructions DIY ? MB Medic) ?
Is the resetting absolutely necessary or it's just a recommendation ?
In the MB workshop they told me, if i replace the conductor plate, and i don't make the adaptation, the car won't even move...

Thanx,
Daniel
 

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93 SL500, 95 SL320, 96 S320, 98 S500, 2002 E320 4Matic Wagon & A little 91 5.0 FORD Mustang
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Hello everybody,

it's maybe late, but i also have some issues with the transmission. The shifting of a C 240 (W203, year 2003) sometimes isn't fine. It has the 722.6 tran.
I also plan to rebuild the transmission.
There is a question i can't find a clear answer for it.
If i replace the conductor plate, will the TCU accept it?
You write here, i have to use the StarDiag to reset the adaptations.
You mean by "resetting the adaptation" this procedure (Reset Transmission Adaptive Shifting - How to Programming Instructions DIY ? MB Medic) ?
Is the resetting absolutely necessary or it's just a recommendation ?
In the MB workshop they told me, if i replace the conductor plate, and i don't make the adaptation, the car won't even move...

Thanx,
Daniel

Daniel,

Welcome to Benzworld, and thank you for your post!

First I want to say that you posted your thread was on the W140 S-Class section of Benzworld, yet I could leave it there, but the 2nd generation 722.6 you have has some changes not applicable to the 722.6 used in the W140's, and the thread you replied to one valve body part does not apply to you as it was used in the 1st Generation 722.6 of the 90's

My name is Martin, and the Moderator of the W140 forum, and I happen to create the 722.6 rebuild threads, but I think you should have your own thread in the W203 section of Benzworld, but I can help you with all your questions....

1) What issues are you having with your 03 722.6 ?
2) Before you rebuild lets go over what is wrong, but these 722.6's last a long time.
3) If you replace the conductor plate, the TCU will accept any conductor plate of any make, but.... some of those super cheap conductor plates on Ebay do not really work well, and it has been documented by some, so avoid those $70/$80 dollar units.
4) The adaptions can be reset in MBStar, but you can clear them with your key like in post #1 of this thread:

http://www.benzworld.org/forums/w210-e-class/1329576-wow-diy-transmission-comp-reset.html

Here is a more formal way

http://www.benzworld.org/forums/w210-e-class/1387073-post-graduate-education-your-22-6x.html

5) Is it absolutely necessary to reset no. The car will shift all the gears pretty good with no problem.

6) About the car not moving after the conductor replacement, a fallacy in the longest way.... If you have a defective conductor plate, worse case you will be in full-limp mode of 2nd gear and reverse. Really what you are looking for in bad conductor plate is ruptured speed sensor, or a speed sensor with a hairline crack viewed with a magnifier-those are a no no...

The true way to identify a bad conductor plate is to measure the two speed signals at the TCU with a dual trace oscilloscope like in the attachment...

Now, In MB Star one can perform a test to find out how worn are your frictions are. Here is a thread on it.

http://www.benzworld.org/forums/w140-s-class/2212242-handy-way-determine-how-worn-out.html

The MB Star to get is the one on post 14, and I have that same one, but you need to get it configured to the Dell D630 as you need a true RS232 port not a USB to RS232 converter, so buy a working D630 on Craigslist or Ebay, and the Chinese unit will come with a hardrive, and you will install the drive on the Dell, and activate the software. Support just ask it on the same thread, but do not want to go through all of that. Paul600600 sell systems with live one on one support.

http://www.benzworld.org/forums/r129-sl-class/2315329-got-my-mb-star-c4-diagnostic.html

Now, fluid in the TCM will make the transmission go wonky, and 98%/99% of the time you can clean it with electrical contact cleaner. here is how I do it..
Your TCM I think is located under the front passenger foot carpet under a plate held down with two 10mm nuts:

http://www.benzworld.org/forums/w21...e-questions-testimony-please.html#post9039089

Also, your shifter bushings can cause problems too, so check them out too...

http://www.benzworld.org/forums/w210-e-class/1413815-photo-diy-shifter-bushing-replacement.html

Lastly, If you want to rebuild, I have all the service manuals and 300 or so High-Resolution photos. The 722.6 of any flavor is the best tranny to DIY for the first timer it is real easy.

http://www.benzworld.org/forums/w140-s-class/2544649-new-revised-722-6-service-manual.html

Really, what is wrong with your 722.6??


Martin
 

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Discussion Starter · #3 ·
Hi Martin,

many thanx for your answer. This is the MOST complete and informative help i ever received.
The problems with the transmission are in the following situations:

1) the shifting in the lower gears (i guess 2nd or 3rd) is jerky.
Not the upshifting (if i accelerate), but the downshifting. More precisely: if i slow up to 30-40mph and the car shifts back from 4th (i guess) to 2nd or 3rd gear, it feels like an old manual transmission if you are hasty with the clutch.

2) if the car stays and i put in R, i have to put on gas, otherwise the car doesn't move. After putting on gas, there is a stronger jerk.

3) if i drive slowly, and i put on gas for a short time, then i take my foot away from the accelerator, then i repeat this procedure, it feels like a manual transmission (it's really wonky). I guess the lockup-clutch of the torque converter get's not released.


Regarding the conductor plate: i can't see no processor or other integrated-circuit on it. So i was also wondering why should i adapt the TCU :)
My plan is to replace the:
conductor plate
solenoids valves
o-rings, springs (like in the Sonnax-kit: https://www.sonnax.com/parts/3052-zip-kit)

and clean up the valve body.
 

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ASTG Manual 722.6

I HAVE THE ATSG MANUAL FOR THE 722.6 TRANSMISSION IF ANYONE NEEDS IT !!

I can email it or shoot you whatever page you may need

Its a LIFE SAVER for anyone doing any work either on the transmission or the valve body
 

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Discussion Starter · #5 ·

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93 SL500, 95 SL320, 96 S320, 98 S500, 2002 E320 4Matic Wagon & A little 91 5.0 FORD Mustang
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Hi Martin,

many thanx for your answer. This is the MOST complete and informative help i ever received.
The problems with the transmission are in the following situations:

1) the shifting in the lower gears (i guess 2nd or 3rd) is jerky.
Not the upshifting (if i accelerate), but the downshifting. More precisely: if i slow up to 30-40mph and the car shifts back from 4th (i guess) to 2nd or 3rd gear, it feels like an old manual transmission if you are hasty with the clutch.

2) if the car stays and i put in R, i have to put on gas, otherwise the car doesn't move. After putting on gas, there is a stronger jerk.

3) if i drive slowly, and i put on gas for a short time, then i take my foot away from the accelerator, then i repeat this procedure, it feels like a manual transmission (it's really wonky). I guess the lockup-clutch of the torque converter get's not released.


Regarding the conductor plate: i can't see no processor or other integrated-circuit on it. So i was also wondering why should i adapt the TCU :)
My plan is to replace the:
conductor plate
solenoids valves
o-rings, springs (like in the Sonnax-kit: https://www.sonnax.com/parts/3052-zip-kit)

and clean up the valve body.
You are welcome.

Transmissions cannot be covered in one post, so I have to write these replies with LOTS of links, and all the manuals, and there are three different ones, yet no one manual is perfect. You got to follow my links always on my posts...All the literature is there...

You need to have certain conditions met with a 722.6 before addressing problems.

How old is your fluid? you have the testing dipstick? How many Kilometers on your transmission?No fluid in the TCM. Did a adaption reset?

The norm is the torque converter lock-up solenoid seal is the first one to fail, and sadly Mercedes does not sell the seal by itself, nor does it sell the shifter seals. One either has to buy a aftermarket rebuild kit which includes the solenoid seals, or do this-Post13:

http://www.benzworld.org/forums/w14...722-6-transmission-computer.html#post16973138

The link you provided is to an FORD transmission, and Sonnax does not make a zip-kit for the 722.6.

The overlap kit for shift valves may solve your problem, or worth doing before a rebuild.

https://www.sonnax.com/units/211-722-6

https://www.sonnax.com/parts/2317-master-overlap-control-valve-sleeve-kit

And...Torque Converter damper valve piston

https://www.sonnax.com/parts/2325-tcc-damper-valve-kit

http://www.benzworld.org/forums/w211-e-class/2508625-solved-transmission-shift-problems.html

Do these, and see what happens,

Martin
 

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Discussion Starter · #7 ·
How old is your fluid? you have the testing dipstick? How many Kilometers on your transmission?No fluid in the TCM. Did a adaption reset?
Again thank you very much for your support.
The car has 122k km in it. The transmission fluid was completely flushed at 116k km. This was about half year ago. I also have the dipstick for the tran. Till now i didn't do anything with the TCM. I don't know if it has oil or not.
I did alredy a manual adaptation reset described in the previous link, but didn't help.
After flushing the fluid it helped a bit. But now i have the same problems.
In the MB workshop the did a software update of the TCM. This also had some positive effect, but now this is also away.
An other thing i noticed: if the car is cold, the shifting is much smoother, than it gets warm.
(There is a sensor for oil temperature or oil level on the conductor plate i guess...)
 

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You are welcome!!

The conductor plate has thermistor on it to lengthen, or shorten the shift cycles, but from that I do not know what else it might do.

The table is out of one of three service manuals I have up on that link. It is out of the Daimler Chrysler manual. The ETC document is there too...

You can check the ohms cold at whatever your instrument cluster says the temperature is, and check it hot too, but you need to disconnect the connector from the TCM...

It will be on the small connector-the one with the CAN bus twisted wires. It will wires 33 and 34, and the shifter must be out of park.

I do not think this thermistor will be your problem, but it will be with the overlap or the damper valve in the valvebody.

Martin
 

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Three years ago when my 722.6 ( C240 ) when to limp mode on freeway and after was a downshift problem ( 105K miles) but all I did was a Johnson & Johnson band aid fix by replacement of Conductor plate , connector ,filter and fresh fluid , It was good and back to normal til now @ 130K it is starting shifting problem , harsh, some time flare and slipping to reverse at neutral , ran fine after cool down ..I am thinking hard about maybe it time for new Sonnax master overlap control valve sleeve kit 68942-05K restores necessary hydraulic control loss . It is a big job for DIY .hope to hear from your guys best advises .
 

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Discussion Starter · #10 ·
You are welcome.

Transmissions cannot be covered in one post, so I have to write these replies with LOTS of links, and all the manuals, and there are three different ones, yet no one manual is perfect. You got to follow my links always on my posts...All the literature is there...

You need to have certain conditions met with a 722.6 before addressing problems.

How old is your fluid? you have the testing dipstick? How many Kilometers on your transmission?No fluid in the TCM. Did a adaption reset?

The norm is the torque converter lock-up solenoid seal is the first one to fail, and sadly Mercedes does not sell the seal by itself, nor does it sell the shifter seals. One either has to buy a aftermarket rebuild kit which includes the solenoid seals, or do this-Post13:

https://www.benzworld.org/forums/w1...722-6-transmission-computer.html#post16973138

The link you provided is to an FORD transmission, and Sonnax does not make a zip-kit for the 722.6.

The overlap kit for shift valves may solve your problem, or worth doing before a rebuild.

https://www.sonnax.com/units/211-722-6

https://www.sonnax.com/parts/2317-master-overlap-control-valve-sleeve-kit

And...Torque Converter damper valve piston

https://www.sonnax.com/parts/2325-tcc-damper-valve-kit

https://www.benzworld.org/forums/w211-e-class/2508625-solved-transmission-shift-problems.html

Do these, and see what happens,

Martin

For some month ago i had shifting issues with the automatic transmission. The hydraulic control unit was completely disassembled and cleaned but this didn't solve the problem.
The real problem was corrosion in the gearbox and in the hydraulic unit as you can see on the pictures. The transmission oil is circulated through the cooling system, but the original one gets leaky after some times. As the result the coolant (especially the water, that forms of it after some years, if the coolant is not changed frequently) leaks through the radiator into the oil.
Finally to solve the problem, the transmission had to be rebuilt. Clutch pack, ball bearing, and some other component was replaced, and also the torque converter was renewed.
 

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CURRENT: 2011 SL550 FORMER: C300, ML350, CLK550 Cabriolet, C240, ML320, 300TD
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Yes, the defective Valeo radiators allow coolant and transmission oil to mix and that can damage the transmission if not fixed quickly.
 

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Hi. I hope I'm on the correct thread, if not I apologize. I need to replace my conductor plate. My mechanic told me I had to go through the dealer. I could just get one off Ebay, right?
Somewhere in the 250 range? Please advise
 

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Welcome to the forum @LVBenz - please take a moment to read the information on the link below. It explains how to update your user profile so that your car's details and your location appear on each post below your avatar. This is good information for others to know when trying to help. It also has good information about how the forums are organized and how to use the search feature:

Find your Forum Section, Navigate & Search

If your car has the 722.6 5-speed transmission, the conductor plate does NOT need any special coding and can be simply replaced. If you have the 7-speed, then it contains the TCU, which is a "theft-relevant part" and requires SCN coding. There are "ways" around that, but without some hacking, it's a dealer job. I'f you have your car's model and year listed in your profile, I could tell you which one you have.
 
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