Finally A FIX for W211 (722.6 box) cold engine stall when switching to D or R from P

[Charlierojo14]

Several threads in MBO (and elsewhere) have dealt with this “mysterious issue”. These MBO threads were interrupted in 2010 without (that I am aware of) the problem being identified and solved.

I own a 2005 Mercedes E220CDI with 230.000 km on it that is suffering from this very same cold stall issue for the last 6 months.

In a rather succinct way, what happens is:

Engine started after car being parked overnight. Engine starts and idles very smoothly, but the moment D or R are selected from P, the engine stalls. If left idling (in my case) for as long as 8 minutes (depending on ambient temperature) one can switch from P to D or R without the engine stalling. Car runs very smoothly shortly afterwards. Engine stalling only happens “once a day” meaning that you can park your car for several hours and then be able to start the engine and instantly drive away without the engine stalling.

Several MBO members have reported and dealt with this issue: rich.g.williams, reuben and others made some real good contributions in (see last few pages)

http://forums.mercedesclub.org.uk/showthread.php?t=56976

The bottom line was that after a lot of effort, creative thinking and many $$$$ spent in trial and error “repairs” and infinite frustration, the cold engine stall issue went unsolved.

The torque converter and more specifically the torque converter clutch (TCC) was suspected the culprit for this cold stall issue. However no one could come out with a sensible explanation and proof of what could be causing the failure so the problem went unsolved.

I have run across an article published in the Torque Converter Rebuilders Association (TCRA) August 2010 issue which describes what appears as the identification of the root cause and fix for this cold stall issue.

Mercedes 722.6: Cold Stall/TCC Shudder Part 1

https://dokumen.tips/documents/torq...on-mercedes-7226-wp-converter-rebuilders.html

Mercedes 722.6: Cold Stall/TCC Shudder Part 2

https://wp.tcraonline.com/wp-content/uploads/2011/10/2010_september_newsletter.pdf

The research was sponsored by SONNAX who now manufactures and sells a simple Clutch Release Kit that can be fit in the TCC by a torque converter rebuilder:

https://www.sonnax.com/parts/3910-clutch-release-kit

I am still finding my way to have this kit mounted in my torque converter in Spain, so I have no personal feedback yet about its effectivity in solving the issue but I thought you would be interested.

 

[star]

Just seen this. Tc problem. We just get the tc rebuilt and then re adapt.

 

[bembo449]

my fathers auto boxed kia sorento had the same problem , the fix was a new fuel rail pressure sensor

 

[Doug1234]

I have an 06 Jeep grand cherokee with the om642 and the 722.6 box albeit in four wheel drive guise.
I have a shudder that can occur on a cold start after about 20 seconds of running and then engaging gear (drive or reverse) but mine only occurs when dash temp display reads between 7-9 deg outside.
When it occurs the headlights if on will dim, it never stalls its just a hiccup.
Jeep bumf says slow engagement of drive or reverse on starting after standing overnight is the norm for these boxes as converter drains down.
It does not do it all the time , maybe once a week. I did put it down to a software glitch as the temps it occurs at are also where the tick over revs are held higher on a cold start and these drops of revs as engine warms are quite noticeable as they do not slowly wind down it just jumps to the next level ie from 1000 say 800 then down to 650 rpm.
That warm spell we had a month ago with temps of 14 odd deg in mornings meant it did not occur ,anyway in six months its no worse so its just become normal cold start behaviour now.
Here is a bit more reading I had bookmarked a while ago
https://www.sonnax.com/tech_resources/22-mercedes-722-6-cold-stall-tcc-shudder-part-1

 

[Charlierojo14]

Thanks Doug1234. This Sonnax article that you share is the one that I had come across with when searching for a solution to the engine stall. That is actually the first one that I included in my post above. First and second included in my post are actually the 2 parts of said article published by which Sonnax in the Torque Converter Rebuilders Association (TCRA) August 2010 issue.

My car also exhibits the shudder and RPM drop when D or R is engaged but only when the engine is warm enough (the engine just stalls when is cold).

Sonnax researched this behaviour in 2010 together with a collaborating Indy, identified the root cause and devised a solution.

Their findings are very well summarized in the first paragraphs of the Mercedes 722.6 Cold Stall/TCC Shudder Part 2 SONNAX article; see link above:

"... technicians found that centrifugal force acting on oil trapped between the TCC piston and cover in the 722.6 converters was applying the clutch on cold start up. They also learned that the cold stall issue could be eliminated by forcing the oil out of the cavity between the piston and cover. Finding the root cause of the cold stall issue - and the subsequent fix - solved many other customer complaints and symptoms, including downshift shudders and tugging sensations."

The fix that they developed is a (torque converter) Clutch release Kit (see below) which is equipped with 10 springs able to force the oil out of the cavity between the piston and torque converter cover, thus disengaging the torque converter clutch eliminating cold engine stall and shudders.

 

[Doug1234]

Ok here is an update on my issue with the shudder on my Jeep.
My shudder has been caused by a dead glow plug (no 6 ).
Now there were no eml or codes stored (Icarsoft bcc2 Jeep specific reader) so no indication of a bad plug and the glow light on dash behaved normally.
I run biodiesel and after switching to 100% bio I noticed a faint puff of smoke in the mornings on a cold start.
Now fuel quality affects severity of the shudder.

Running mainly on diesel (around at least 70% ) there was the odd shudder until engine about 1/4 warm.

70% biodiesel (with 1ml per litre 2ehn) and 30% diesel it would shudder more but it was completely random and no rhythm to when it would occur.

100% biodiesel with 1ml 2ehn per litre and it was guaranteed to occur at least every 25 seconds or so.

100% biodiesel with no 2ehn additive and it shuddered every 8-9 seconds constantly until engine had been running at least five or six minutes.

I only notice shudder when engine is ticking over and in gear in stationary traffic, ticking over at 600rpm with a quick 200rpm jump to 800rpm and back to normal in the blink of an eye, once driving its not felt at all.

Because of its random behaviour I did start to believe this shudder was caused by the egr possibly sticking.
So if you notice any odd running when cold and your fuel computer starts showing you are using an extra litre or so per 100km then check your glow plugs and relay out.

 

[busva]

Hello and sorry for resurrecting such an old thread, but this looks like the closest thing to solve my problems.

The symptoms are exactly as posted (cold engine stall when shifting into gear, no stall when warmed up) - nothing helped so far.

Have you got the sonnax clutch release kit installed in the end and did it solve your issue?
Thanks,
Ivan

Several threads in MBO (and elsewhere) have dealt with this “mysterious issue”. These MBO threads were interrupted in 2010 without (that I am aware of) the problem being identified and solved.

I own a 2005 Mercedes E220CDI with 230.000 km on it that is suffering from this very same cold stall issue for the last 6 months.

In a rather succinct way, what happens is:

Engine started after car being parked overnight. Engine starts and idles very smoothly, but the moment D or R are selected from P, the engine stalls. If left idling (in my case) for as long as 8 minutes (depending on ambient temperature) one can switch from P to D or R without the engine stalling. Car runs very smoothly shortly afterwards. Engine stalling only happens “once a day” meaning that you can park your car for several hours and then be able to start the engine and instantly drive away without the engine stalling.

Several MBO members have reported and dealt with this issue: rich.g.williams, reuben and others made some real good contributions in (see last few pages)

http://forums.mercedesclub.org.uk/showthread.php?t=56976

The bottom line was that after a lot of effort, creative thinking and many $$$$ spent in trial and error “repairs” and infinite frustration, the cold engine stall issue went unsolved.

The torque converter and more specifically the torque converter clutch (TCC) was suspected the culprit for this cold stall issue. However no one could come out with a sensible explanation and proof of what could be causing the failure so the problem went unsolved.

I have run across an article published in the Torque Converter Rebuilders Association (TCRA) August 2010 issue which describes what appears as the identification of the root cause and fix for this cold stall issue.

Mercedes 722.6: Cold Stall/TCC Shudder Part 1

https://dokumen.tips/documents/torq...on-mercedes-7226-wp-converter-rebuilders.html

Mercedes 722.6: Cold Stall/TCC Shudder Part 2

https://wp.tcraonline.com/wp-content/uploads/2011/10/2010_september_newsletter.pdf

The research was sponsored by SONNAX who now manufactures and sells a simple Clutch Release Kit that can be fit in the TCC by a torque converter rebuilder:

https://www.sonnax.com/parts/3910-clutch-release-kit

I am still finding my way to have this kit mounted in my torque converter in Spain, so I have no personal feedback yet about its effectivity in solving the issue but I thought you would be interested.

 

[Charlierojo14]

Hello and sorry for resurrecting such an old thread, but this looks like the closest thing to solve my problems.

The symptoms are exactly as posted (cold engine stall when shifting into gear, no stall when warmed up) - nothing helped so far.

Have you got the sonnax clutch release kit installed in the end and did it solve your issue?
Thanks,
Ivan

Hi Ivan,

First of all no need to apologise for "reopening" this discussion no matter how "old" the thread might be.

I have not got installed the Sonnax kit yet. I had planned to get it done in January but, due to the Covid-19 pandemic travel restrictions, I did not get to use my car much during the cold weather months. My car also had a turbocharger failure (with 242.000 km on it) which forced me change my car repair spending priorities.

As it may also be your case, in the warm/hot months the issue lessens to a great extend or even disappears. With ambient temperatures no lower that 14ºC what I do is warm up the engine for just 1 or 2 minutes and then, with the left foot on the brake and the right foot "ready" on the gas pedal, I engage "R". The engine slows down sharply but it does not stall if I quickly (but moderately) press -and-release the gas pedal for a couple of times or so. Once the engine is up and running it won't stall whenever "D" or "R" is engaged and you can then drive the car normally.

I am convinced that fitting the Sonnax kit to the converter will definitely solve the cold stall issue. I currently plan to get it done probably early next year.

In my thorough research to try to identify the cold stall root cause, I looked for and obtained feedback from converter repair shops in the USA and in Spain. I found that some of them fit the Sonnax kit as a "standard" in their Mercedes 722.6 torque converter repairs.

Check this link to Ohio (USA) Consolidated Vehicle Converters- Mercedes Benz converters :

http://www.peachparts.com/shopforum...erter-core-cvc-mercedes-torque-converters.pdf.

In this pdf document CVC state that "CVC REBUILDS ALL MERCEDES BENZ MULTIPLE CLUTCH PLATE UNITS WITH SONNAX’S CLUTCH PERFORMANCE KIT. THIS KIT ADDRESSES COMPLAINTS OF POOR TORQUE CONVERTER CLUTCH
PERFORMANCE, THE MOST NOTICEABLE PROBLEM IS COLD ENGINE STALL ON ENGAGEMENT, WITH
OTHER COMPLAINTS SUCH AS SHUDDER, ENGINE LUGGING AND CLUTCH WEAR ALSO POSSIBLE."

In short, though I have not tried it yet, my conclusion about the fix is that the SONNAX Clutch Release Kit provides an effective, affordable way, to eliminate the cold stall issue without the costly trial-and-error attempts to correct the fault.

It is clear to me that a brand new 722.6 transmission does not require the help of the springs to function properly but, once the transmission gets a good load of miles on it, probably the resulting wear causes that residual fluids gets trapped behind the clutch piston and then the springs are needed to force the residual fluid back to restore normal (sound) clutch functionality.

I believe that the added springs and modified plate really are elements that were lacking from the Torque Converter Clutch's original design, and nare not needed on a brand new transmission.

With these new elements the Torque Converter Clutch original design is greatly improved, and this improvement is needed on (some) high milage 722.6 equipped Mercedes cars to prevent the cold stalling issue.

Ivan, I hope that this is helpful to you. Look forward to hearing back from you if you decide to go for this fix.

 

[James Parry]

After suffering with this same issue for nearly a year, I've finally had my w204 looked at by a local Mercedes Indy and a replacement TC has been suggested at £826 + VAT.

Not overly keen on paying this for it to not fix the issue...anyone had any luck, or have any updates on this issue?

Has anyone taken the plunge with the SONNAX kit? I've had a peek online and there are no prices or anything listed....

 

[ajlsl600]

And benz say what,about this issue.I wonder if debris builds up overtime like a sludge and sits there at shutdown then takes a while to flush thru at each morning cold start.

 

[Charlierojo14]

Hi James,

I did a thorough search on this issue and one thing I know for sure I would not do is replace the TC with a "standard" unit. Many owners were fed up with this very annoying issue and tried everything, including TC replacement, spending big money to no avail.

I found a local TC repair shop which is a member of AT (Automatic Choice) Group. AT is a European distributor of SONNAX, and as such they can provide (and install) the SONNAX kit.

AC is listed in SONNAX web page: https://www.sonnax.com/distributors/88-automatic-choice.

In my case, the local (Spain) TC shop told me that they fit all rebuilt Mercedes 722.6 TC with the SONNAX kit. They quoted me a price of 424€ (including VAT) for the TC refurbishing job.

My approach was to have my trusted independent shop to take the TC out of the car and then have the TC repair shop refurbish it (including the SONNAX kit) and have it mounted it again in the car. Total budget, including TC refurbishing, small parts and labor was 1085€

I never got around doing it because of other car expenses (replacing busted turbo) I had to prioritise instead, but I am sure this is the course of action I will take sooner or later to try and fix the issue.

Hope this is of help to you.

 

[James Parry]

Hi James,

I did a thorough search on this issue and one thing I know for sure I would not do is replace the TC with a "standard" unit. Many owners were fed up with this very annoying issue and tried everything, including TC replacement, spending big money to no avail.

I found a local TC repair shop which is a member of AT (Automatic Choice) Group. AT is a European distributor of SONNAX, and as such they can provide (and install) the SONNAX kit.

AC is listed in SONNAX web page: https://www.sonnax.com/distributors/88-automatic-choice.

In my case, the local (Spain) TC shop told me that they fit all rebuilt Mercedes 722.6 TC with the SONNAX kit. They quoted me a price of 424€ (including VAT) for the TC refurbishing job.

My approach was to have my trusted independent shop to take the TC out of the car and then have the TC repair shop refurbish it (including the SONNAX kit) and have it mounted it again in the car. Total budget, including TC refurbishing, small parts and labor was 1085€

I never got around doing it because of other car expenses (replacing busted turbo) I had to prioritise instead, but I am sure this is the course of action I will take sooner or later to try and fix the issue.

Hope this is of help to you.

Thanks for your very detailed response!

I've done a bit of digging myself and spoken to a retired Gearbox specialist over the phone who has replaced many 772.6's and his response was "You shouldn't have to replace the TC, in all my years, I've never seen a damaged one and your car has far less power and torque than previous models that have the V8 and V12's"

Basically, he thinks there's two issues, low gearbox fluid, or a faulty Conductor plate.

I'm not dismissing what he says - but I'm skeptical. I had my transmission fluid changed and the conductor plate changed at the same time. But hey, I'll start with the cheapest fixes first!

I'll report back when I make some progress.

Cheers

 

[James Parry]

I've not made any progress with my Cold Stalling issue thus far. Has anyone else?

I've been looking for the SONNAX rebuild kit, but I believe the only way to get this fitted, Is to go through a verified rebuilder, so I'm awaiting on a response by email for a list of rebuilders.

Another thought though, couldn't the TC be replaced by another Torque Converter? (Seeing as the issue lies within the TC itself?) Or is there more to it?

 

[Charlierojo14]

Hi James,

Sorry not be able to provide a "proof of concept" or rather a "proof of solution" here, as I have not yet implemented the SONNAX KIT to my Mercedes TC.

However, I think I understand what the solution, found empirically by Wayne Russell, of Russell Auto Inc. in Manchester, N.H, is about.

The bottom line is, as explained by Wayne Russell, that, for some unknown reason (but certainly related to transmission parts wear) , in some high mileage 722.6 gearboxes (probably not in many of them) the line feeding the ATF to apply the necessary pressure on the TC clutch, fails to drain the ATF back out of the clutch piston circuit, thus remaining there.

As a consequence of this, if the car is left for a long time (overnight) to cool down, the now more viscous ATF that is "trapped" behind the clutch-apply piston, and due to the centrifugal forces that originate when the engine is restarted, does actuate on the clutch, linking the engine to the wheels and thus causing the engine to stall.

If the engine is allowed to idle (engine and ATF heating up) for (depending on ambient temperature) 2, 3, 4…in my case up to 8 minutes, before engaging D o R, there is a harsher initial engament but the engine does not stall and the car runs fine from that moment on.

So to adress your question “couldn't the TC be replaced by another Torque Converter? , based on the above it would not solve the issue, because there is (probably) nothing wrong with your TC, but with something that wore off in your transmission (see explanation above). The beauty of Mr Russell’s solution is that some tiny springs fitted to the TC clutch plate solves the stalling issue.

So I would not replace your TC with a new (or a rebuilt one) that lacks the springs), because the issue is elsewhere in the transmission. If you do that I believe that you would be spending money to no avail.

When I decide to get mine fixed, I will definitely get the SONNAX kit (with the tiny springs) fitted in my own TC by a reputable TC shop.

Hope that the above expalnatios are useful to you. Please keep us posted as to what you decide to do.

 

[alexanderfoti]

Thanks for your very detailed response!

I've done a bit of digging myself and spoken to a retired Gearbox specialist over the phone who has replaced many 772.6's and his response was "You shouldn't have to replace the TC, in all my years, I've never seen a damaged one and your car has far less power and torque than previous models that have the V8 and V12's"

Basically, he thinks there's two issues, low gearbox fluid, or a faulty Conductor plate.

I'm not dismissing what he says - but I'm skeptical. I had my transmission fluid changed and the conductor plate changed at the same time. But hey, I'll start with the cheapest fixes first!

I'll report back when I make some progress.

Cheers

I would be as well. I have changed loads of TC's across a range of models for this or similar faults.

 

[James Parry]

Hi James,

Sorry not be able to provide a "proof of concept" or rather a "proof of solution" here, as I have not yet implemented the SONNAX KIT to my Mercedes TC.

However, I think I understand what the solution, found empirically by Wayne Russell, of Russell Auto Inc. in Manchester, N.H, is about.

The bottom line is, as explained by Wayne Russell, that, for some unknown reason (but certainly related to transmission parts wear) , in some high mileage 722.6 gearboxes (probably not in many of them) the line feeding the ATF to apply the necessary pressure on the TC clutch, fails to drain the ATF back out of the clutch piston circuit, thus remaining there.

As a consequence of this, if the car is left for a long time (overnight) to cool down, the now more viscous ATF that is "trapped" behind the clutch-apply piston, and due to the centrifugal forces that originate when the engine is restarted, does actuate on the clutch, linking the engine to the wheels and thus causing the engine to stall.

If the engine is allowed to idle (engine and ATF heating up) for (depending on ambient temperature) 2, 3, 4…in my case up to 8 minutes, before engaging D o R, there is a harsher initial engament but the engine does not stall and the car runs fine from that moment on.

So to adress your question “couldn't the TC be replaced by another Torque Converter? , based on the above it would not solve the issue, because there is (probably) nothing wrong with your TC, but with something that wore off in your transmission (see explanation above). The beauty of Mr Russell’s solution is that some tiny springs fitted to the TC clutch plate solves the stalling issue.

So I would not replace your TC with a new (or a rebuilt one) that lacks the springs), because the issue is elsewhere in the transmission. If you do that I believe that you would be spending money to no avail.

When I decide to get mine fixed, I will definitely get the SONNAX kit (with the tiny springs) fitted in my own TC by a reputable TC shop.

Hope that the above expalnatios are useful to you. Please keep us posted as to what you decide to do.

Thanks for that explanation - I have an update about my car (although not overly positive)

I decided to contact the suppliers of the SONNAX kit in the UK, whom then forwarded me onto a local transmission specialist who were authorised to fit the SONNAX kits.

I had a lengthy chat with the garage owner, described my fault and everything I'd done in the meantime to remedy it. He smiled, and said "Yeah, I know the fault, and it's definitely not your Torque Converter! It's your Valve Body, well, parts of it. We can fit the kit, but we need to know why the valve body has been damaged in the first place - if there's debris in your box, it could be done for. When the gearboxes get to 150k, they are fairly worn by then" (mine has done 150k)

So, he suggested I start with using "Shudder Stop" or something along those lines to flush it out, with new oil, seals, filter, etc.

He quoted £220 + VAT. That's without the SONNAX kit, or the installation of it.

I've decided to cut my losses, as my car is approaching it's MOT and would need three new tyres, and it also needs an Alternator pulley changed. So I sold my car for £2000.

It's a shame, I liked the car, but it would've been a grand minimum, and it didn't seem worth it to me.

 

[Charlierojo14]

Thanks James for your reply.

Sorry that you decided to get rid of the car. It seems to me it was a very sensible decision as the approach suggested by the garage to troubleshoot the transmission spelled potentially big investement ahead.

I found the "Shudder Stop"concept very interesting. I just Googled the term and found a "magical" product named "Instant Shudder Fixx" from LubeGard. Browsing through the buyer´s feedback section (Amazon) it seems, to say the least, is not very effective.

At least in my case I experience no TC shudder. It runs just fine once I warm up the engine (ATF). I have replaced the ATF + filter and at some time also the transmission electronic plate. The valve body is most likely not the culprit of the cold stall issue (and very expensive to troubleshoot) , as the transmission works just fine once it is warmed up before engaging any gear(only needed in temperatures of the like of 13ºC or below, and only after the car has stood still overnight).

 

[Wighty]

Thanks James for your reply.

Sorry that you decided to get rid of the car. It seems to me it was a very sensible decision as the approach suggested by the garage to troubleshoot the transmission spelled potentially big investement ahead.

I found the "Shudder Stop"concept very interesting. I just Googled the term and found a "magical" product named "Instant Shudder Fixx" from LubeGard. Browsing through the buyer´s feedback section (Amazon) it seems, to say the least, is not very effective.

At least in my case I experience no TC shudder. It runs just fine once I warm up the engine (ATF). I have replaced the ATF + filter and at some time also the transmission electronic plate. The valve body is most likely not the culprit of the cold stall issue (and very expensive to troubleshoot) , as the transmission works just fine once it is warmed up before engaging any gear(only needed in temperatures of the like of 13ºC or below, and only after the car has stood still overnight).

I’m sure I’ve heard of people on this forum using shudder fix in the last few years

 

[alexanderfoti]

I have used it on a few cars with rumbling TC's. Worked well, but as above, the cars were not worth much, certainly not worth pulling the box off and doing the TC the proper way, so nothing to loose.