Hello!

I bought a CLS 55 AMG 2 months ago. This week, without any particular signs, a problem arose that the car produces a transmission error after driving about 10 km. It starts to slip in the current gear, and then the transmission is no longer engaged. After a reboot, everything is fine for a while, then it starts all over again. Furthermore, a strange sound appeared along with it, similar to the screeching of a compressor. The car produces the following error codes (P0730 or P2560 or P2069). I checked the oil level with a dipstick when the engine was running after driving 10 km, and I think there is a lot of fluid in it compared to the mark. The stick must be the right size, it showed perfect results when measuring another 722.6 shifter. The liquid does not look or smell burnt. The car had a complete gearbox change at the end of 2015 in Switzerland by the previous owner (in the attached pictures), at which time it had 185,000 km. The car currently has 230,000 km on it, so the new transmission has run 45,000 km. I don't want to believe that it would have a mechanical fault after traveling such a distance. I removed the TCU unit located on the right side of the interior, and I found no traces of oil leakage either in the line or in the connectors. I will take it to a mechanic next week, where the bottom cover will be removed, I will tell him to look at the connector there as well. What can I expect? Can a control unit change and a fluid filter change solve the problem? Has anyone had a similar problem that they solved relatively easily. I would not like to go into a gearbox exchange, given the low running condition of the current gearbox. This is also why I chose the 55 AMG, because based on the opinions on the forum, I came to the conclusion that it is much more reliable than the 63 AMG engine and transmission. The car has not been neglected at all, it can be said to be in perfect condition and its entire history can be traced with all invoices.
Attached the pictures and a video. The noise -------->

You Tube

Thank you!
Szilárd

 

Did you do the transmission reset? I followed this video and used the second way. It might very well be the conductor plate. Also oil seems to be too much. I would: replace the conductor plate, replace the filter, replace the connector, gasket & all O-rings for the solenoids. Refill properly and perform the reset and try again.

 

Hi!

Thank you the reply. I tried earlier - before the actual problem - this method (first in the video). I will try again, and if it not work, i try the second.

 

Then it probably wont help you. Do you know if the conductor plate has been replaced or if its still the original one?

I replaced mine last year when it had about 190.000kms on the clock. it seems it had the original one. More pics in my build thread (see signature)

 

Yesterday I removed the TCU unit (in the interior). It looked good, the connections too, no trace of oil was visible. I cleaned the connectors, tried the recommended transmission restart methods (both) I start the car, drive it for a few km, everything works perfectly, there is no annoying noise. While I'm looking at the oil level, it also increases on the dipstick as it should based on the experiences I've read. I keep driving the car when the noise first appears. I check the level again, and in this case it already shows above the max mark. I will remove the lower cover this weekend and check the condition of the connector. Will get an oil and filter change next week to start.
If I need to buy a new TCU unit or conductor plate, would any part for the 722.6 transmission be fine, or does the AMG require a special part?

 

I bought a aftermarket conductor plate with partnr: 1402701161

 

Since the problem is giving me sleepless nights, today I planned to take a visual look at the connector. The noise could also be heard after starting the car. In a standing position, I changed all the gears with a 10-second wait. After that I checked the level, it seemed perfectly fine (25 degree range) The car ran for a few minutes, then I checked the level again, it seemed to rise linearly and read around 80 degrees. It seems fast, which is strange because of the short time spent standing still. The sound was still present. Then I stopped the engine, after a few seconds I started it. The sound is gone. I switched gears again and watched a level. Now it was halfway between 80 degrees and 25 degrees, so it was less than the previous measurement after a few minutes, and there was no sound. From this I conclude that the appearance of the sound is related to the oil pressure. The liquid looks pinkish and has no burnt smell. Could the filter be clogged? From what? Is there a problem with the oil pump? The previous owner (from whom I bought) changed the oil filter and connector 15,000 kilometers ago. On the basis of the previous transmission replacement invoice 45,000 kilometers ago (at the very first Swiss owner), looking at the article numbers on the paper, the replacement of the conductor plate cannot be seen separately. I've had many cars with automatic transmission and currently have 3 others in use besides the AMG, but I've never had any problems with any of them. I'm always careful when buying a car, and this car was perfect in every way (until this moment). What else I'm thinking, if the oil cooler wasn't replaced during the previous transmission change, couldn't it have become clogged? In the end, I didn't check the connector because I didn't even get out of the car. I don't want to use it more than necessary, I can take it to have it checked on Tuesday.
Is there any other not too complicated solution? Instead of conductor plate and TCU. For example, a solenoid problem due to a broken spring? If the oil pump were bad, could it show intermittent operation? How complicated is it to replace the pump? I still don't understand it all, there are 45,000 km in the transmission...
Thanks for the helpful comments so far!

 

Hi, I replied to your YouTube video and told you exactly what the problem is.. it's neither connector or tcu. if there were a problem with the connector car wouldn't start. it will be stuck in C mode on the dash and won't change to S or M when you push the button at the shifter.
it is 100% a bad o-ring on your solenoids, a clogged screen within the valve body and maybe one of the speed sensors on the conductor plate has failed. You literally need 2 tools. 7mm socket to remove the nut in center on connector and a 30 torx to remove transmission pan and valve body.. it may take a couple hours if it's your first time but definitely a do it yourself job.
you mentioned the oil seemed to warm up fast and that the transmission was previously replaced.. if so there is a possibility the torque converter wasn't put back unto the transmission housing all the way to engage the oil pump tabs because it may feel like it's all the way on when reassembling but if the 2 grooves for the oil pump don't properly align then it doesn't go all the way on. This could actually break the oil pump tabs when tightening the transmission back to the engine. The car will still work but the oil would be hot which causes the O rings to fail faster than usual resulting in no movement. Also the broken oil tabs can be chewed up over time and the metal fragments block the tiny screens inside the valve body..
here's what to do . Disconnect one of the oil cooler lines coming off the transmission and start car briefly just to see if you have good oil flow to verify pump is working. If pump is bad then you need to remove and disassemble entire transmission to replace the inner gear of the oil pump. If oil pump is good, then you simply need to clean the valve body, and change the orings on the solenoids. Sometimes the speed sensors on the conductor plate can just be wiped clean and they will work again but they are so cheap at around $50 it's not worth the effort putting the dirty conductor plate back in the car. So before you do anything else order yourself a cheap conductor plate kit $60 on ebay(comes with the new oil filter and plug) and get a set of o rings $15 on ebay. Clean the 4 little screen filters inside the valve body and reinstall it..

 

I would also suggest you forget about the concept of having a mechanic if you have this car... you are the mechanic now and the best person to fix your own car, you will learn everything over time, don't waste money on so called mechanics, there just going to screw you over and do a half a$$ed job since it isnt their car. Do it yourself!

 

Hi Dadaddy!

Thanks for the tips. All I did today was check the connector. I pulled it apart, it was quite oily. After removing the plastic covers, everything looked good to the eye. I cleaned the connector and put it back. The situation is unchanged. Although I drove quite a few kilometers today. The sound appeared sometimes, but disappeared for a while after the car was restarted. There were no other problems or error codes with the car today, although I didn't drive it much, but I drove it a lot in one place and checked the level several times. The oil level is on the lower line of the 80 degree mark after a warm run, so it's good. When the sound appears under the same conditions, the oil level seems very high. I didn't have time for anything else, next week I will continue with the suggestions you wrote (oil flow in the cooler, conductor plate cleaning, replacement of solenoid o-rings). If there is new news, I will report immediately.

 

Without any words...

 

 

Can a fluid change fix it? Or don't be naive...

 

There seem to be metal shavings in the filter. Maybe the transmission oil pump bearing has gone bad. It's somewhat common now, for those bearings to fail

 

I rebuild my E55 tranny, torque converter and new radiator for $4800 USD 3 years ago. Good luck.

 

Update:I drained the liquid and cleaned the tray. I filled the missing fluid with new fluid. I drove a bit. After that, I took the tray off again, there were fewer metal filings in it. I refilled the missing fluid again, then replaced the filter. This was 1 week ago, since then I have driven about 100 kilometers with the car both in the city and on the country road, and the problem has disappeared. it works perfectly in all gears and modes, no errors or error codes. I plan to use it and drive another 200 kilometers in it. After that, I take the tray off again and check if there are any metal filings left in it. I hope it will be okay.

 

Update? Did you ever have any more transmission problems?

 

Sorry, i forgot to reply long time ago. I think it was a happy end, since then the car and the tranny works perfectly. I haven't used it much (approx 2000 km), it's a hobby car but everything looks fine.

 

In the past in 'S' mode i felt some annoying vibration in the third and fourth gear in low rpms (1000-1200) in city driving that went out when i changed gear manually to a lower gear for increase rpm. Some days ago with my wife and doggy started to a short trip to another city. In this travelling i kicked sometimes the car with full throttle and enjoyed the sound and the amazing acceleration. After when went back to home on with a fully normal drivestyle i felt some slipping and vibrating in 2000 rpm third and fourth gear. I knew, it was the transmission... After this happening very carefully drove to home. The next day i bring the car to a test drive and check faulr codes with Xentry-Das. Not found some codes, but after a long drive i heard a similiar noise that i heard 1.5 years ago. I think, i need to find another transmission.

 

A couple of months ago, I had the same issues that you were facing. In my case, I found a lot of metal shavings in the oil and the gearbox was rebuilt as a result of that

More info: https://mbworld.org/forums/c219/8443...ml#post9015803 (keep scrolling to see the aftermath)

 

I read some reviews about this car (CLS 55 AMG). The reason what I choose this, because the engine and the transmission is 'bulletproof'... The metal shave color in my fluid looks more copper, I think my fault is not (just) the wandler : What was the total price to a tranny rebuild and what's the time for guarantee? I found a local specialist. The starter price is at least 4,000 EUR if the tranny does not have a big problem... The other possibility to find a working tranny from another car that was damaged by and accident. This way is cheaper, but the chance to get a similar fault later is more than the rebuilt tranny. But I heard some wrong review about the rebuilt tranny also. In Hungary this specialist gives 6 months or 10,000 km for guarantee.

 

I paid 3800 euro for the rebuild (with new torque converter) with 1 year guarantee, which is a common price within Netherlands. I also found a shop in Germany which have rebuilt 722.6 ready to go for about 2500 euro, and then you only need to get it mounted

 

From my experience I have learned a number of things. 1. The engine/trans is bulletproof on the 55 AMG but it must be maintained. 2. The weakness of the transmission is the conductor plate. 3. It’s plastic to save weight and it warps after a period of time because of the heat and needs to be replaced. 4. Oil infiltration into the connector causes poor connection. 5. It can’t be cleaned effectively. 6. If you buy one thing from a dealer make it the plug not for the plug but for the seals (o rings). They are the best made and the rest are junk (ask me how I know). 7. You cannot clear the trans codes without a professional scanner or Star system. 8. I bought a Star system because it was actually cheaper than a pro scanner and it can tell you if your car burps and I’m dead serious. Told me the thermostat was bad. I told my wrench man (and close friend) about it. Everything was normal, no change in temp or heat. He pulled it and the machine was correct. It was stuck partially open (or closed depending on how you look at it). That’s the only diagnostic tool I’ll ever own as long as I have a Mercedes. I’ve replaced 2 conductor plates on the CLS and 1 in my ML-55. As a point f experience the CLS has a cheezey plastic pan, it leaked and warped from heat. The pan on the ML is metal. I switched out the plastic for metal and it never leaked again. Each time the only way to clear the trans module was to use the Star. And lastly I totally agree. I own Mercedes in an area where if it is not a Ford or Chevy they can’t fix it so I am my own mechanic even though I work a white collar job. They are a fine auto but unless you are really wealthy or in a large city where there are indies who do enough work on foreign cars that they know what they are doing you need to invest in good tools and hook up with a good forum and learn about your car.

 

Good points!

But a plastic pan on the CLS55?

 

Indeed. Plastic. I guess some brilliant tech thought it would be a great way to save a few ounces by going plastic. Moron didn’t think of the heat factor just like the conductor plate. I would have ordered the same garbage plastic except I also own an ML-55 AMG with the same engine and trans and the pan there was metal. I put almost 300k miles on that car. Replaced the conductor plate once but the metal pan never leaked the entire time I owned it.