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722.6 Transmission jerk/slipping in winter cold

28K views 9 replies 6 participants last post by  meooem1 
#1 ·
Hello,

I have been reading for a long time this great forum and I am going to post here my case looking for some advise. First let's describe the patient.

It's a 2004 W211 E270CDI (OM646 Engine, not sold in the USA) with 120.000km on it. Everything working great except the automatic tranny. In the winter cold, and only the, when I first star the car in the morning and pull it out of the garage with low throttle, the first or perhaps the first couple of shifting happen with a jerk as if in a manual transmission car the clutch was released too early. If after that jerk/slipping I fully release the throttle I can hear a little noise and the car seems to have more engine braking than desired.
During the rest of the day the transmission works perfectly, and out of the cold winter it works great, too. I assume it's directly related to the oil temperature.

The gearbox has been serviced twice with full flush (last time 20.000km ago) with MB fluid, the electrical plug was changed during each flush although it was not leaking. Oil level is ok measured with engine running, hot oil and in P. It's not affected by the glycol issue. I have a SDS/Xentry terminal, no fault stored. Just in case, engine mounts are not in very good condition, but the car does not show any vibration at idle yet.

I am not any MB specialist, just an aerospace engineer who loves cars even more than aeroplanes. In any case, I have reading the 722.6 common failures -as well as all kind of technical data of the transmission- and mine appears to the related to the Torque Converter lock-up clutch. As the symptons are being showed just once a day and perhaps 20 days a year, I am not going crazy or opening the gearbox. I have in my mind a few steps:

- Check the behaviour in Winter/Comfort setting instead of Sport program.
- With SDS, disable the Torque Converter lock-up clutch and check the behaviour.
- With SDS, read all the adaptation parameters to see the "life" of the transmission.
Unless otherwise evident appears, perform a Torque converter lockup adaptation with SDS.

Should I do/check anything different?

Thanks
 
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#3 ·
I repair many of these transmissions, and SDS will not tell you if you have a temperature problem with the solenoids as it can only discover open or shorted solenoids, so it is useless for this...

The easy thing you can do is reset your adaptations first, and drive the car, so it relearns..

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

Next, i would measure the thermistor on the conductor plate on a morning it should be close to any liquid in a metal container.. I wrote this a while ago that may help..Post 5

http://www.benzworld.org/forums/w140-s-class/1839898-722-6-cold-weather-pls-help.html#post7039434

You need the pin out to measure it from the TCM(Transmission Control Module) pins..You need the ETC-Error-Code document from post 22

http://www.benzworld.org/forums/w140-s-class/1691375-no-transmission-fluid-symptoms.html#post5629503

If the thermister checks out, then for the sake of checking. I inspect the TCM for for fluid-Unplug the two black connectors from the TCM, and rotate the TCM upside-down to see if fluid leaks-like in post 5

http://www.benzworld.org/forums/w210-e-class/1570724-my-attempt-replacing-transmission-plug.html

If you find fluid, all bets are off until this is cleaned up... This is how you clean it:

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

And you need to change your circular connector as that was the reason for this, and post one is how you change it...

http://www.benzworld.org/forums/w210-e-class/1570724-my-attempt-replacing-transmission-plug.html

The other thing to do is to inspect the solenoid seals, and the filters on the two black regulation solenoids. The over drive solenoid seal gets brittle hard(it is the dark gray looking solenoid), but check for malleable seals

http://www.benzworld.org/forums/w21...ve-body-rebuilt-transmission.html#post9558858

The last result is the torque converter spring lever in it like in these article is being affected...

Mercedes 722.6: Cold Stall/TCC Shudder, Part 1 - Sonnax

Mercedes 722.6: Cold Stall/TCC Shudder, Part 2 - Sonnax

Here in the USA. CVC torque converters have sonnax updates in them. They are about $200 USD...

Torque Converters Distributors Page - Consolidated Vehicle Converters, Remanufacturing Torque Converters for Automatic Transmissions


Hope it helps,

Martin

PS. I do not have a W211, but my W210 and W140 have a 722.6
 
#5 ·
You are welcome !

One has to share the knowledge, and advance human kind. It makes the world go better...

This is applicable to the 722.6 ONLY. The 722.9 is a different bird.

I hang out at the W140, W210 or R129 forums-This ABC suspension stuff scares me....:wink I will settle for a car with a blown transmission any day...:angel


Pitasoft,

I forgot to include something that can be done above ground with SDS. Once your transmission is working well when warmed-up. You should do this test to find out how worn-out your transmission. It only works on the 722.6.....

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

I think you should be a able to do this...

All the best,

Martin
 
#8 ·
722.6 Transmission Jerk when cold

I've been meaning to post this as I know others have this problem. I have battled the same problem with my 04 E320. The first time I replaced the conductor plate, and the plug (was leaking). This worked for about 9 mo. until it got cold again. This time it was jerking even in the warm weather and would behave normally once up to temp. It was only during the few miles and did it in the "C" mode and in manual mode indicating a clutch lock-up issue. I had the car diagnosed with STAR which produced no error codes. I replaced the PWM solenoid. Both times I changed the filter and ATF fluid. So far so good. Shifts great.

Paul
 
#9 ·
I've been meaning to post this as I know others have this problem. I have battled the same problem with my 04 E320. The first time I replaced the conductor plate, and the plug (was leaking). This worked for about 9 mo. until it got cold again. This time it was jerking even in the warm weather and would behave normally once up to temp. It was only during the few miles and did it in the "C" mode and in manual mode indicating a clutch lock-up issue. I had the car diagnosed with STAR which produced no error codes. I replaced the PWM solenoid. Both times I changed the filter and ATF fluid. So far so good. Shifts great.

Paul
I am quite suspicious about the PWM solenoid. I drove the car again recently and I could feel as if the lock-up clutch was being applied step by step instead of smoothly while cold. The part is not expensive, but the labour is. I'll probably wait until the next oil flush.


Thanks for sharing your experience Paul
 
#10 ·
Pita I've been dealing with a similar problem with my 04 e320. It happens while I am coasting through a parking lot or in stop and go traffic. I will get what feels like a hard downshift with the related rpm rise. It is worse when first started. I also get a weird shift when going 30 to 40 mph and I let off gas to coast to a dip in the road. When I get back on the gas the rpms rise momentarly and then the lower gear catches. Most people probably wouldn't even notice it...but I am nuts when it comes to cars.

Fluid has been changed every 20 to 30k and no codes.

Is this similar to what your car is doing?

Any thoughts on my problem from the experts?
 
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