What disconnects the transmission when you are in park?

[rich.g.williams]

one further possible reason - incorrect ATF some of the older ATF's (such as Dexron II) do not have the same properties and do not comply with the MB ATF spec 236.12 even Dexron III is not recommended for the 722.6 transmission

 

[MPK]

My E200K has the same problem of stalling in D or R first thing in the morning. The only thing is the TC was changed in October - done around 3k miles since. This was one of the problems that caused me to have the TC changed in the first place. However, I have contacted the company in Birmingham who fitted it and they are having the car back tomorrow for a day or two to work through the issue (hopefully). Before contacting them I had changed the 02 sensor, CPS and completed an ATF oil and filter change with no positive result. It would seem to me that the TC is playing up, but I'm no gearbox specialist and hopefully this isn't cost me a further arm and leg to have put right, especially as 'her indoors' says "just live with it and move the between D to N to R to work the oil in the mornings - what's the problem?".
It's just not right, when the TC has just been replaced that this issue should be present.
I'll keep you updated as to their diagnosis.

Hi Kevsta - Welcome to the forum.

I have similar problems with my 722.6 gearbox that only occur when left overnight and cold.
Can you tell me how you first diagnosed the fault ? - MB or Gearbox specialist.

Were they able to read any codes ?
Or did you have the codes read via STAR before getting any work done ?

Was it expensive to replace the TC ? - I assume a reconditioned TC.

Was the gearbox companies diagnostics able to "adapt" the new TC to the box ?

Best of luck with the fix - Please keep us posted.

Mike

 

[reuben]

Good to see more people are coming forward with this problem since I guess it means more suggestions and more people eliminating possible causes.

I should add that I had the lockup clutch solenoid changed when I got the gearbox service done and it didn't fix the problem. I am worried that the only option I have is to change the TC. The price for doing this with a reconditioned TC is about 700 inc vat from an indy or a fair amount more from MB. I just wish I could see the input and output speed of the TC as that would confirm the cause of the problem!

I am very keen to do the LED test - have you got any more info on this? For example where is that connector?

 

[rich.g.williams]

reuben,

in N the engine and TC output shafts are turning, you can deduce that once the gearbox engages a gear when cold (any gear it doesn't matter) it loads the TC and obliges the TC output shaft to stop turning

normally the TC simply slips (easy at low engine rpm) in these instances it seems that it doesn't slip so the engine stalls

the TC is locking either because the TC lock up clutch is engaged (by solenoid etc) or because the clutch plates are binding or because the TC is faulty/damaged

if the TC remained locked up after start you would have a lot of problems, stalling, noise and vibration

too much ATF or incorrect ATF or presence of water could make the TC lock up clutch bind when cold

the TC lock up clutch mechanism could have collapsed

Please PM me if you want more details as regards the LED test

 

[Kevsta]

MPK,
Thanks for your message. The replacement TC was reconditioned.
The original symptons were obviously what is currently being discussed plus the delay and heavy 'clunk' into gear. This had been getting progressively worse until March this year when I took it to the local ex-Merc mechanic indy who changed the ATF and filter. This seemed to ease the problem for a short while then the clunking returned and I decided to bite the bullet and took it to Drivers in Birmingham. Before I took it I read all the various forums which all pointed to a duff TC. Drivers agreed. Unfortunately, now although the gearchanges are smooth (once running) this stalling issue persists. The car is with them now having dropped it off late yesterday afternoon. I'm just waiting for a phone call to find out what 'the damage' is!! ..... I'll keep the post updated.

 

[MPK]

Kevsta / Reuben - Firstly, Happy new year.

Any updates or good news stories on your gearbox issues ?

 

[Kevsta]

MPK,
Happy New Year to you too.
The update on mine is I picked up my car from 'Drivers' in Birmingham who told me that they had replaced the TC and control unit. As I drove home (approx 40 miles) there was a droning sound around 50mph in top gear. We were due to travel to my in-laws for the weekend so I thought lets take it for a long drive to see what the issues are! This is a 400 mile round trip. Well this proved to be quite interesting as the droning continued on both journeys plus when I stopped to fill with LPG in Kent I could not move the gearstick out of Drive to set off. A new one on me and I had no idea how to deal with this, being an automatic there was no way it could be pushed! Fortunately, I had Drivers' phone number and I rang them to find out how I can move the car. This turned out to be quite simple - a pen or screw driver into the small 'flap' at the back of the gear stick allows it to be disengaged - took me about 30 seconds and definitely something worth knowing. Anyway, needless to say the car went back to Drivers on Monday and the control unit was replaced. It runs perfectly now but ...... the stalling issue remains!! I think I'll live with it for the moment as I only need to move the gearstick a couple of times between R & D to move the oil about before I set off, but I will continue to see if this problem can be solved.

 

[rich.g.williams]

a percentage of incorrect ATF oil (or water) may cause this

some of the older ATF's (such as Dexron II) do not have the same properties and do not comply with the MB ATF spec 236.12 even Dexron III is not recommended for the 722.6 transmission

the new TC is still actuated by ATF oil supply from the transmission valve block and this oil passes through drill holes in the TC output shaft so the fault could be here

 

[MPK]

Thanks for the update Kevsta.

So, you have had the TC and control unit replaced.
ATF oil and filter changed.
And STILL STALLS ??

Frustrating !!

Could it be that the "new" TC needs to be adapted in some way using STAR ?

It sounds like your no further forward on this problem, but a lot lighter in pocket.

What do you do next ?
- Did you get any codes read ?

Mike.

 

[rich.g.williams]

I doubt that adapting the TC would affect this in any way because when first starting, at idle revs, there is no way that the ETC will turn on the TC Lock-Up solenoid, it doesn't make any sense.

 

[Kevsta]

Rich,

Are you saying that the problem is more than likely ATF related?

MPK, I've got to say that Drivers in Brum have not charged me any more money since the original TC change, although I was expecting some cost involved. They have a 12 month unlimited mileage warranty on their work and to date have lived up to it so far and with calm, polite customer service.
Would recommend to anyone despite the issues I am having.

 

[rich.g.williams]

a percentage of incorrect ATF oil (or water) may cause this

some of the older ATF's (such as Dexron II) do not have the same properties and do not comply with the MB ATF spec 236.12 even Dexron III is not recommended for the 722.6 transmission

the new TC is still actuated by ATF oil supply from the transmission valve block and this oil passes through drill holes in the TC output shaft so the fault could be here

I am saying if you have as little as 30% Dexron II (or some water) in there you will have TC binding when cold.

I am also saying that a problem in the Valve Block (TC lockup valve or TC lockup solenoid) could cause this by partially actuating the lockup clutch when it should not be actuated

 

[reuben]

Hi Kevsta, I'm sorry to hear that the TC change has not solved the problem.

I got used to braking with the left foot, revving the engine a little and then pulling it into drive when starting which means it rarely stalls.

When I have time I am going to look into the cause of the problem in a little more detail. I dont plan to replace the TC until I am sure this is the problem, and your experience makes me even less keen to replace it!

 

[reuben]

To update this thread, tomorrow I am finally having a test done on the car which will confirm to me whether it is the lock up clutch that is causing this problem of stalling from cold.

The test I have wanted to do ever since starting this thread was to see the input and output rpm of the TC in park, before a stall like this occurs. Then to see the same values once the stalling has stopped happening.

This will confirm whether the lockup clutch is sticking and turnout its output at near engine rpm which is causing the stalling as drive is engaged.

So I have a friendly mechanic doing this test with his diagnostics tomorrow morning and I'll report back.

 

[Charlierojo14]

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

Apologies for posting here as this is a really old thread but I am not aware if the cold stalling issue was ever resolved.

I have some new information about a supposedly proven fix involving the TCC that I would like to share.

Please let me know if It is ok to post here or else start a new thread.

 

[James Parry]

Was there ever a solution found to this issue?