S owner

Thank you for reading.

Hello MBWorld,

I would like to share my story with my weekend car.

***Keep in mind that the manual mentions that during cold start, the gears change at higher rpm to warm the catalytic converter faster.

Recently I noticed that either with cold or warm engine, 2nd or 3rd gear over rev without changing to the next gear only after some time.
Two days ago I covered 8 miles (12.5 km) with cold engine and stopped at a junction. I then step on the gas (no kick down) and the car over rev stuck in one gear; 2nd or 3rd, and as I was expecting a gear change,*** instead at 5000 rpm (red mark) the message "Drive to workshop without changing gear" came up and the car died, eventually coming to a stop. Drive wasn't selected so I couldn't just drive to the garage. I remove the key and put it back to start the engine and there is a clunking noise coming from where the box and the engine meets. No smell or smokes. I did not select a gear but call a platform straight to the dealer who told me that the TC does not engage and there is also the possibility that shrapnel sent to the box. The rep is asking € 2500 for a new TC and € 500 to open the box for further examination. For potential box recondition € 7000 and for a new one € 10000.
The indie told me that the clutch was worn and wasn't engaging, leading to a failure and apparently putting the car in safe/limp mode with one gear. He suggest TC and box recondition with one year warranty as it's a better option than a used box that we don't know it's history.

My questions is:

1. Why such an expensive car didn't warn me beforehand with an engine light or the message "Drive to workshop without changing gear" to allow me to Drive to the workshop safe, instead of letting me thinking that it's going to change gear eventually leading to a disaster? :/
2. Do you think this is normal for the age and mileage of the car?
3. Does it play a role that I step on the gas while the engine temperature wasn't at normal operating conditions?
4. Or the box was about time to die after all...

All these questions in my head don't let me sleep so I seek your opinion.

• 01/01/2006 S 320 CDI V221 UK imported in Cyprus 16/04/2014
• Service on time at the dealer
• 04/11/2016 last transmission oil replace 722.9 (7 liters) at 140060 miles (and every 40000 miles before that)
• 29/09/2020 last service at 145621 miles (the service wasn't asking for transmission oil replace)
• 19/12/2020 current miles during breakdown 145751 (234565 km)
• New starter and consumer batteries

seiltaenzerin

Hi S owner,

From my understanding, the W221 pre-facelift models (2007-2009), and specifically the early 2007 models, were notorious for engine and transmission issues. With that in mind, I do not think your situation sounds abnormal—unfortunately. While I don't know the details of what has happened to you, I suspect that you did not receive a warning message beforehand simply because the computer did not have enough time to react before it was already too late. However, I am not too sure.

Now, when it comes to stepping on the gas (or "flooring it"), that is something you should avoid when the vehicle is not warm. Until the car reaches operating temperatures, the engine oil is not providing maximum lubrication properties—and I would assume that also applies to transmission oil.

I hope you can resolve this issue without too much hassle to you.

BOTUS

100% normal Mercedes "feature"

does seem you got 5 years and 60k miles further than it was supposed to

S owner

The car is going to the indie for another used box and TC recondition €5000, as I'm planning to sell. I do not think I can stand any other surprise financially and psychologically.

S owner

Reading this I feel a bit relieved strangely...

auburn2

1. Sounds like a catastrophic failure of the torque converter or pump. You usually will not get a warning on that.
2. It is not abnormal. These things happen, you would hope for 250,000 miles or more but transmissions do fail
3. No
4. Probably

The price quoted you seems very high compared to US prices. A new 722.9 from Mercedes would be about $3500 in the US which is half of what he quoted you for a rebuilt one.

S owner

Yes I don't know in the rest EU but in CY prices are very high.

UPDATE
S-Class on the way to the indie. Since I'm planning to sell, he decided to put another box used ~€4000 and recondition my TC €1000.
Initially I was thinking it was time to go (sell for parts) but he convince me that after fixing it we will be able to find a potential buyer easier.

artim808

Where you can get new trans for $3500? This is very good price

BOTUS

failure of the box to shift is not unusual,

these boxes aren't complex, but they aren't well made and they have a number of known issues.

• The actual way it has different gear ratios is all normal automatic (wet mutliplate clutches and epicyclic gear trains)
• The way it manages to stop drive when the vehicle is stationary is like a normal automatic (a sloppy Torque Converter [TC] basically there's no mechanical connection between the engine and gearbox just a fan in a bucket of oil) which can be between 0% and 98% efficient as required
• Like all autos a pump pressurises the fluid inside the box, this is used to stop cavitation in the TC and provides the pressure for all the gear changes.
• The way it attempts to increase efficiency of the Torque converter (TC) at certain speed by an electric solenoid locking the fan in the bucket of oil, to give 1 to 1 drive, is just like normal automatics from 1990s
• What also changed around 1990, instead of oil pressure, shuttle valves and springs inside a very expensive, complex, finely machined valve body (which directed oil flow to operate the clutches and bands to lock different parts of the spriograph to get the different ratios). A basic computer and some cheap electro hydraulic solenoids replaced the valve body and they now control the flow of oil to the bands and clutches with better ability to influence change points (and adds some adaptive capability to allow for the shoddy build and fast wear components).

those changes brought the need to put electronics inside the gearbox for the first time. So we get a sandwich of electro hydraulic solenoids, a computer, a few sensors and the mechanical bits... this brought an opportunity to increase complexity and design in new failure modes. Once they decided to throw in more ratios to increase fuel efficiency / performance, it all got too weak with too many bits to wear out, and with deliberate failure modes it causes lots of fun.

• the most common failure is the electro conductor plate between the gears and the actuator…. its has a 2 dollar speed sensor that dies about 7 to 9 year mark. With this playing up or dead, stuck in the wrong gear is normal. Its about $1000 fitted (they also added immobiliser info locked to each car so a nightmare to swap - although naughty software exits to get round it)
• the next failure is the TC clutch it gives up and can cause stalling and or poor shifts. Gearbox out and refurbished TC fitted $2500
• a lack of frequent trans fluid changes causes both above to happen earlier / more frequently (maybe metal making electrical connections it shouldn't or just ripping the clutch to bits?), but also brings the opportunity to create real damage elsewhere. Swarf and wear from clutches in all early 7g boxes from the terrible build quality make the trans fluid full off dirt, metal and other debris and it rips critical oil seals to bits and clogs the electro hydraulic actuators. Once changes become slow it increases wear (just like they designed it) and if the filters on each actuator become too blocked, changes become odd or muddled and it needs a full rebuild or replacement

your failure seems unusual, it might have just been a electro plate or dirty actuator...
and an oil change might get away with things for a year or so. But the noises are not normal... It sounds like the guy looking at it doesn't really have the right equipment or experience
but sadly at your mileage, 8hrs labour, some new seals, clutches, a TC and electo plate should be expected


.

S owner

Thanks for the information

S owner

The thing is, since the last trans oil change (4/11/2016), the car covered roughly 6000 mi and during the last service 29/9/2020 I ask the tech if it's necessary to change the trans oil as well and he said "well it only covered 6000 mi in 4 years so it will be a waste to change it again. Also the service is not bringing up trans oil change."

If only I could go back in time...

S owner

I was hoping for 250,000 mi and sometimes I'm wondering if I could reach that mileage by using the manual mode instead and drive like a turtle hehe

auburn2

it could be a little more or less depnding on year and trim. here is one online outlet;
mbonlineparts.com
222-270-79-30-80
$3254.90

usually my local dealer will give me close to thier price. not quite match it but then there is no shipping either

S owner

OK so I was browsing google today and found this old thread where cassiri in post #3 had the same experience back in November 2007.

https://www.benzworld.org/threads/he...2/post-2632793

BOTUS

you need to know what's gone wrong, nasty noises and the car not wanting to move, sounds worse than the usual glitches. Get the sump off and see what mess it has, if the fluid was changed (it doesn't repair worn clutches , dirty solenoids or a failed electro plate) but if its still clean inside and not a hideous mess it might be a much cheaper fix than total replacement

proper diagnostic kit will show shed loads of info to give a merc trans expert a good idea, plus the visual check inside and you have a sensible starting point.

S owner

Yes thanks for the suggestion he is going to do that - open it to have an idea BUT since he is doing the trouble and for my mileage, the trans needs total recondition, new clutches, seals, etc., the cost of that exceeding that of a used trans. I know a refurbished trans will ultimately be relatively bulletproof but I have to look also at the expense in the end.

BOTUS

agree, but if moving the car on, if an electro plate fix gets it as good as it was, that's more sensible for your pocket?

most S class' end life though this sort or failure and or a suspension strut air leak. people with their head in the sand like to argue I'm mistaken. The truth is they built them like this post 1990. they just moved with the times.... rip off the poor, steal all the money, ruin the world and have lots of expensive trinkets - don't worry if the current stuff is dead inside 3 years - somewhere you'll have stolen another few million - and thus can just get a different colour one delivered (probably a colour your latest Russian bed warmer prefers?).

S owner

Hi BOTUS, because I'm curious as to what exactly happened and to prove that I'm not hardheaded and open to opinions like yours, I call the indie to change the plan by fixing my current trans and TC rather than fitting another box. He will open it and let you know guys. FYI the fluid level isn't low with a first look.

tx170754

Extremely positive thread, especially in these times, thank you 🥶

Arrie

"TC does not engage" is completely wrong statement from your dealer. TC is always engaged. The only thing that would not engage is the clutch that locks the TC as one body. If this clutch fails (does not engage) the car would still move by the actual action of the TC.

For me it sounds you lost the pump. Without the pump no gear in the box will engage and car will not move.

Pump is mounted in the start of the gear box and is easy to change out without opening the box itself.

You are in big danger of being ripped off, just saying...

S owner

I think Arrie hit the nail on the head. That would explain the noise coming from the start of the gear box.


Noted

BOTUS

this is the one bit I didn't include in my description of the contents inside an auto.

Yep, like all autos a pump pressurises the fluid in the TC to stop cavitation (of that fan in the bucket of oil) and provides the pressure for all the gear changes (via those electro hydraulic solenoids operating the clutches). Never heard one fail on a Merc, but not close to any one regularly working on them. And of course anything could fail.

S owner

https://www.transmissiondigest.com/722-9-pump-failure/

S owner

Alright guys so the indi told me that:

1. Oil was black and burnt although oil level was correct (he couldn't believe the car covered 6000 miles only).
2. Showed me the seized pump bushing on the converter neck resulting in pump breakage and bell housing scratching.
3. Converter clutch was worn.
4. There is a speed sensor error but he don't know if it appeared before or after the failure.
5. He find it strange that somebody mark the outer bell housing with a yellow spray (could be that work was done before on the transmission).

Also it looks like from the last transmission service four years and 6000 miles ago, the merc service station replaced only 7 ltr of oil. The indi told me that they did not replace the TC oil. I visited the same service station and they confirm it with the excuse that my TC (722.902) doesn't have a drain plug while the indi insist otherwise.

During the last oil replace, the remaining old oil from the TC was mixed with the new oil. To my question, the official service station replied that's not an issue for a disaster neither the four year time.

What do you guys think? Could the old oil from the TC mixed up with the new oil, create a corrosive material that could be responsible?

BOTUS

its normal very early 7g TC had a drain bung allegedly... but not on later ones

the TC full of dirty oil is a misnomer… the gearbox cooler and half the insides can hold another 2 litres anyway... the best way is to swap the fluid go for a drive and come back and do it again. And then it turns out the best thing is for an expert to drop each of the 6 solenoids wipe a magnet over the gauze and give them a rinse too

what you describe to me sounds like the first trans fluid change was NEVER done and or they didn't do the big filter (so that blocked, starved things and it all fell to bits making the fluid filthy)
or
the second guy is showing you a different box's internals