Hi all,

Quick backstory on my issue, I've owned my 06 CLS55 (posting in the W211 forum because same transmission) for about 2 months now, it has been running and driving just fine up until recently. Once I received the car I ran it through star and it had no stored codes for the transmission. The car was acting normally during regular and spirited driving, no harsh lockups, no flare shifts, nothing out of the ordinary. During a WOT event it shifted into neutral. I let off it and it picked up a gear with no input from me at 1300rpm and I babied it home but it drove and shifted fine (no limp mode). After about 2 weeks the problem came back, shifted into neutral, picked up a gear at about 1300rpms, but this time when I tried to baby it back home, it went back into neutral very quickly. I decided to tow it as to not do anymore damage. Unfortunately when the tow arrived, I experienced total loss of drive. Any gear selection would act like N.
I got it home, ran it through star and found codes P2503, P2500, P2561, P220A & P2563. I also checked the solenoid valves section in star and found that y3/6y2 (shift pressure solenoid) was pulling over an amp but it had 0 pressure (I assumed this is why it could not get out of N). I browsed the forums here and since it had a speed sensor code and a solenoid wasn't getting fluid that I would start off by replacing the conductor plate and testing the solenoids.

I drained the fluid and it was brown but didn't smell burned. However, it was quite filled with metal particles. I couldn't feel any grit so the powder was super fine suspended in the fluid, but the transmission pan magnet and both speed sensors were also covered in a layer of metal dust/powder. The filter also had a good amount of metal in it, but I ran fluid through it and it went through. I split the valvebody, found a nice clog below the 6y2 solenoid and I cleaned it out along with the rest of the valvebody. While I had the valvebody out I put in the sonax sleeves and TCC, I replaced the conductor plate and I tested the ohms and actuation of all the solenoids. All solenoids actuated and came back at the low end of the allowable range. I reassembled it back together with a new 13 pin bushing and I checked the TCU for transmission fluid, bone dry.

After reassembly and filling with fluid, checked to the 25 degree mark on the dipstick, I went into star, cleared the codes and reset adaptions. I was under the impression that my loss of drive was due to the transmission going into loss of drive mode as described in the ASTG 2009 manual since I threw 'hard' codes. I checked the 6y2 solenoid and it had pressure and was pulling ~780mA instead of an entire amp.

Unfortunately I still have loss of drive (in S,C &M, gear selector targets R2, first or second gear and CAN signal also targets those gears, but 'actual' gear is N). I am starting to suspect that the transmission pump or the torque converter is the culprit for my loss of drive (due to the fact that second gear limp and reverse should always be hydraulically available). Unfortunately I am a transmission novice and I'm honestly not sure how I would diagnose these issues short of dropping the transmission and physically inspecting them (which id like to avoid until I know whether I am replacing or repairing). Any advice or maybe something I missed would be super helpful. TIA

 

Did you also replace the O-rings for the solenoids? I noticed massive improvement in shifting behavior after replacing them with new O-rings. They should have positive engagement when you push them in the valve body. Did you also replace the 2 filters & 2 strainers? They might've been clogged

The metal particles is a bit concerning though :|

More pictures in my build thread: https://mbworld.org/forums/c219/8443...ml#post8956930

 

I did not replace the o rings, when I tested the solenoids the values came back very low and when I moved the o rings with a tiny flathead, they were still very rubbery and soft which leads me to believe they were fairly new. I also did not replace the screens, strainers or check valve. I did clean and inspect them and visually they were fine.

the amount of metal was concerning (wish I took pictures) but I've seen maybe 10-15 people with double the metal content in their ATF that were able to run it after a conductor plate change.

At this point I've eliminated the valvebody and it's components from the list of things that could be causing my loss of drive. I'm convinced it must be something mechanical otherwise the car would be in limp mode and would have reverse also. I'm leaning towards the transmission pump but it's more of a guess.

 

Unfortunately I don't know too much about the inner workings of the transmission

 

Metal particals....N/G !! There is something going on and it is not good. Could be the converter or clutch plates. More than likely clutch plates down to metal and is why you lose gears.
Trans is very easy to build with good mechanical back round but either way it has to come out. Sorry man.

 

I was worried about the metal particles at first but I saw this illustration in the ASTG 2009 manual. my fluid looked like the one on the left. a lot of particles but very very fine, no grit to them at all.

that being said I didn't have any slipping or harsh lockups until the transmission just lost all drive. The manual mentions that it has a limp home mode for electronic failures (like conductor plate, fluid in tcu) and a separate hydro mechanical limp home mode for mechanical failures. in either mode it has one drive gear and reverse, I have no movement at all. I'll likely drop the transmission regardless, but I would like to have a plan or at least a good theory on what the problem might be before I start this project.

 

No matter what you see for particles it still does not move so must come out if you want to fix it. As long as the electrical signals are getting to the solenoids than it has to be something internal.
Problem is in the forward clutch pack or converter.

 

This guy does a total overhaul with good explanation

 

Well unfortunately I won't be able to drop the transmission until probably Sunday morning so in the meantime I've been just scrolling through the threads looking for other people with the same problems and comparing star data. looking at what codes I had stored

P2503 The gear comparison is negative or the target gear is not reached
P2500 The transmission has an impermissible transmission ratio
P2561 The gear is implausible or the transmission is slipping (2nd)
P220A The speed comparison of y3/6n2 to y3/6n3 is implausible
P2563 The gear is implausible or the transmission is slipping (4th)

I think that the valvebody work did solve some of the underlying problems for these codes. P2503 (055 DTC) has a possible cause listed as y3/6y2, this solenoid was pushing out 0 bar and after I cleaned the valvebody its pushing between 1.9 bar and 5.3 bar. P220A(011 DTC) is for the speed sensors on the conductor plate, at idle and with a little bit of acceleration, the value for these two sensors stays within 1-2 /min.
Anyone know what the DTC for the remaining codes are? P2500, P2561 and P2563. I'll likely update this again on Sunday night or Monday morning once the transmission is finally out.

 

Interesting update.

I was waiting for a friend to come help me drop the transmission and I decided I'd start draining the fluid out while he was driving over. I pulled out the plug. Nothing. Bone dry. I know for a fact I have put in 4.5 qt of shell 134 and measured it with the dipstick multiple times and it was the correct level.
naturally I check with the dipstick just to see and of course it's also bone dry. I throw the plug, torque it and fill it up and turn it on to get the new fluid in there. This time the fluid got up to like 55 degrees but no matter how much I added it wouldn't get above the 25 degree mark.
I had my buddy look under the car and when I put it I'm drive it absolutely sprays out a lot of fluid. I popped off the two square seals and it seems to be coming from the output side of the torque converter. So I assume I blew some kind of seal on the input shaft. I'm gonna start dropping it out either way but at least I have a starting point (and this might end up being a relatively cheap fix)

 

Your all over the place with your discriptions of what's going on. How did it leak out almost 5 qt's ? There should be a huge mess under the car no ??
This leak issue is something new and if all the fluid pushed out then that explains why it does not move on top of what ever other issues it has.

 

When I originally pulled the valve body I missed the pan and covered my driveway with ATF and it's been raining here daily. I haven't noticed a puddle because my driveway has been pretty much wet with rain since the time the car went down. I haven't had a second set of eyes to observe under the car until today. So this leak has probably been happening slowly when the car is off and it only really turns into a heavy leak when the car is put in drive.
I'll finish pulling the transmission and report back when it's done

 

OK now I understand.
So if you are going to tackle this transmission yourself take your time,don't jump around with questions and do everything in order. I can walk you through the best I can online.
I have built these many many times

 

Everything is just about out, unfortunately I don't seem to have anything that can tackle the top bellhouse bolts. I can reach them no problem but rachet with a sizeable breaker bar couldn't do it, 600ftlb impact couldn't do it so I'm stumped. I tried to get them with blaster but who knows how effective that will be.

I'm open to suggestions 😅

 

Very odd....they should come right out for sure. Can't offer any advice except to just keep trying.

 

Been struggling for awhile now, just decided to take one out on the bottom to see and it must be the extentions I'm using. I was able to take the bottom two with medium effort and no breaker bar or impact..
I'm gonna drop the exhaust to give myself a little bit more room to get in there. I wanted to do the exhaust anyways but I wanted to wait until the car was at least running seems a bit counter productive to have a car that sounds amazing but doesn't move... anyways hopefully without those giant cats i can fit a swivel in there and not have to use an extention

 

Oh man I don't see how you are doing it with the exhaust still in place. Get that out of there and make some room !

 

Lol indeed, its not that much work to remove the front section of the exhaust

 

Standard universal to allow for the angle is quite possibly the problem. Use a specific impact universal. Also, support the end of the trans, remove the trans mount then slowily drop the tail a bit to allow better access to those top bolts and give more room for the impact universal. Good luck.

 

I ended up going to get a stiffer extention because i felt like i was getting nowhere. I was able to get it with a breaker bar immediately after switching extentions. Dropped it out and ripped it down. Everything is in fairly good/previously serviced condition except for the transmission pump. It's got 1/3 of one of the ears left and the other one came rattling out when I took the bellhouse off.... well at least I know what blew the oil pump seal out and at least those ears didn't work their way back into the clutches or anything else 🤣
I'm ordering a new oil pump and hopefully I can get this thing back on the road ASAP.

 

Aaaaa hold on, you inspected the rest of the trans and it's good? I guess you got lucky so that's good.

 

Is it fixed ??

 

I just got back from vacation so the car hasn't seen much progress
The transmission was in fairly good condition, I didn't strip it down completely but I took out all the frictions and steels and there was no obvious wear or burnt sections. I was able to swap out the oil pump and get it all stacked up, but when I was putting the case over the transmission stack, it stops about half an inch before closing up. I've seen this in a couple rebuild videos and they just spin the output shaft and it usually drops down and they seal it back up. I tried that trick and it didn't work for me so I'm planning on taking out the output shaft seal and output shaft bearing and the two thrust washers and hopefully that alleviates my problem. The new rear seal should be here tomorrow since I'm likely going to ruin the old one when I remove it tonight and that should be that as far as getting the transmission back into one piece.

 

Any update?