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Discussion Starter #1
I have the dreaded speed sensor issue and it's showing P2767. I'm aware of the process to swap the sensors... But is it better to just go with: circuitboardmedics.com or try the repair?

I Haven't seen many success stories swapping the parts from ebay/Amazon, I'm good at soldering and mechanics work... But my main concern is the transmission as well... And if the time/effort/sensors are worth trying.

So I have a 2007 ml500, and while it has the better vgs2 that can be repaired separately from the valve body my concern is the amount of debris I have in the transmission. I'm more concerned because while the car goes into limp mode and is a permanent (ie resetting codes immediately displays the code/limp mode) so the service should fix this.. It's the concern I have a feeling the transmission pump is not working correctly and I've seen there's a redesigned pump, has anyone successfully upgraded the transmission with the updated pump?

Just to add, I did a transmission flush, and it fixed the original code (I need to check but it was a generic code for bad fluid). But now I know for sure the pump isn't working - whining noise etc/transmission oil smell and limp mode. My concern is in addition to the pump not working and adding debris is that the clutch materials are in the transmission fluid. I'm going to pull the transmission next.... But I've seen some pretty bad bad stuff online regarding the torque converter/pump on the early 722.9s.

Anyway my side question is, if I but another transmission from a ml500/w164, can I just reuse the conductor plate/valve body or is the only option to go with scn coding?? This has to be the best and worst car I've ever worked on... The amount of research I've done is ridiculous and I have full access to Mercedes manual.. But now I'm wondering if I Should just make this a side job and buy a c4/c5 setup... I've never seen such a mess regarding the way Mercedes claims these are theft parts....

My other question... Does the does the transfer case regularly screw up? In addition to the transmission? I'm trying to get this to be a more reliable vehicle... And I hate to say it... But the damn early cvt's on nissan are more reliable (not really but, I've worked on them and....yeah the 722.9 really pissed me off, vs the cvt).

Sorry for the long run on questions, if you need more details let me know.

Thanks in advance!!!
 

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When there is a problem with the transmission, there is no separate icon in the cluster. The ECM is used to notify the driver that there is a prob. with the trans., hence code P2767.

You will need a scanner that can read the code/s in the trans control module. Either you buy your own scanner or take it to a repair shop that can read the codes in the trans. module.

https://www.amazon.com/Autel-MD802-Diagnostic-Diagnoses-Functions/dp/B078WTHK1L/ref=sr_1_3?keywords=autel+elite+MD802&qid=1565898989&s=gateway&sr=8-3/
 

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I have done a torque converter and fluid pump replacement on a 722.9. The torque converter swap is simple once the transmission is dropped. The fluid pump is more difficult because you have to totally unstack the entire transmission.

A few things to note:

1. You need to inspect the back of the bell housing surface to make sure the pump's "impeller" has not chewed into it. If it has, the you really need to replace that half of the bell housing, which is VERY expensive as it's magnesium. An alternative is a thin plate (aftermarket) that you place between the pump and bell housing surface. I have no experience with that.

2. You MUST have the proper tools. Accessing the Torx bolts for the bell housing is a challenge. I used a series of tools. Some very long extensions with universal joints as well as a Craftsman Max Axess socket set. Also, removing the tailpiece from the transmission output shaft requires an impact wrench. I set mine to 600lbft and let it knock on it for about 5 minutes (per bolt) before they came loose.

3. When installing the torque converter into the transmission, the shaft has two notches that lien up with the ears on the fluid pump. It is IMPERATIVE that these be properly aligned so that the torque converter drops fully into the transmission. And you MUST keep it fully inserted while position the transmission back into the car. I used zip ties to hold the torque converter in place and then snipped them off and removed them once everything was mated. If the torque converter is nor properly seated, the bell housing halves will not mate flush - they will be about 1/4 inch apart. Some mechanics figure they will just "pull it in" and in doing so, it will over-stress the flex plate (flywheel) and the fluid pump. Do NOT do that!

4. With the transmission out, go ahead and replace the engine's rear main seal. ANd inspect the flex plate and replace it if it has any cracks, chipped teeth for the starter, or bends/dents on the pulse ring for the CPS.

5. If you don't have SDS (and i suspect you don't as you posted a generic OBDII P-code), you might consider getting it. At the very least, you MUST have WIS for all the details on how to do the transmission work.

And to answer your question about the conductor plate...no, you cannot install a used one as it will already have been SCN-coded to the donor vehicle. Technically, there is a way to erase the coding and make it appear "virgin" so it can be re-coded, but honestly, I'd just fix/replace your original conductor plate. Pull it out before dropping the transmission (removing the valve body saves some weight) and send it off while doing the partial rebuild job.
 

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2009 ML350 164.186 / 272.967 / 722.9
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Way over my head as a DIY, but wonderful example of quality Q/A on this forum. Here is a used spare:


I've dealt with Yancey before...good folks.
 

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Discussion Starter #5
I have done a torque converter and fluid pump replacement on a 722.9. The torque converter swap is simple once the transmission is dropped. The fluid pump is more difficult because you have to totally unstack the entire transmission.

A few things to note:

1. You need to inspect the back of the bell housing surface to make sure the pump's "impeller" has not chewed into it. If it has, the you really need to replace that half of the bell housing, which is VERY expensive as it's magnesium. An alternative is a thin plate (aftermarket) that you place between the pump and bell housing surface. I have no experience with that.

2. You MUST have the proper tools. Accessing the Torx bolts for the bell housing is a challenge. I used a series of tools. Some very long extensions with universal joints as well as a Craftsman Max Axess socket set. Also, removing the tailpiece from the transmission output shaft requires an impact wrench. I set mine to 600lbft and let it knock on it for about 5 minutes (per bolt) before they came loose.

3. When installing the torque converter into the transmission, the shaft has two notches that lien up with the ears on the fluid pump. It is IMPERATIVE that these be properly aligned so that the torque converter drops fully into the transmission. And you MUST keep it fully inserted while position the transmission back into the car. I used zip ties to hold the torque converter in place and then snipped them off and removed them once everything was mated. If the torque converter is nor properly seated, the bell housing halves will not mate flush - they will be about 1/4 inch apart. Some mechanics figure they will just "pull it in" and in doing so, it will over-stress the flex plate (flywheel) and the fluid pump. Do NOT do that!

4. With the transmission out, go ahead and replace the engine's rear main seal. ANd inspect the flex plate and replace it if it has any cracks, chipped teeth for the starter, or bends/dents on the pulse ring for the CPS.

5. If you don't have SDS (and i suspect you don't as you posted a generic OBDII P-code), you might consider getting it. At the very least, you MUST have WIS for all the details on how to do the transmission work.

And to answer your question about the conductor plate...no, you cannot install a used one as it will already have been SCN-coded to the donor vehicle. Technically, there is a way to erase the coding and make it appear "virgin" so it can be re-coded, but honestly, I'd just fix/replace your original conductor plate. Pull it out before dropping the transmission (removing the valve body saves some weight) and send it off while doing the partial rebuild job.
Thanks so much for the details here. Yes, I have access to solid tools so removal shouldn't be an issue and full access to the WIS, but I probably should invest in a better scan tool/consider SDS. With that said... Assuming once I remove the transmission if it's as bad as it could be and the rebuild prices for various parts can cost a ton... Is it possible to use my existing (hopefully repaired) conductor plate in a donor/replacement transmission? I'm concerned with the amount of metal in the pan/valve body. And I'm pretty sure the pump is probably chewed up at a minimum (at least from researching this a ton). I wish this car had the 722.6... The whole SCN thing sucks.

Unfortunately I wasn't the main driver, but the car went into limp mode, and when it got back to the house you could tell the transmission fluid was burnt. In dropping the pan, the fluid isn't the worst I've seen but it's not good either considering the car was probably driven less than 1k miles between the last service.
 

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Discussion Starter #6
Way over my head as a DIY, but wonderful example of quality Q/A on this forum. Here is a used spare:


I've dealt with Yancey before...good folks.
Thanks so much for sharing this.
 

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Discussion Starter #7 (Edited)
When there is a problem with the transmission, there is no separate icon in the cluster. The ECM is used to notify the driver that there is a prob. with the trans., hence code P2767.

You will need a scanner that can read the code/s in the trans control module. Either you buy your own scanner or take it to a repair shop that can read the codes in the trans. module.

https://www.amazon.com/Autel-MD802-Diagnostic-Diagnoses-Functions/dp/B078WTHK1L/ref=sr_1_3?keywords=autel+elite+MD802&qid=1565898989&s=gateway&sr=8-3/
I definitely agree with you that I need a different scanner for better/quality codes from the TCM but I'm pretty certain that the transmission is the issue (and not like a wheel speed sensor, I wish it was...), unfortunately before dropping the pan, just starting the car in the driveway for a short period produced burnt transmission fluid smell.
 

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2010 ML350 4MATIC
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Way over my head as a DIY, but wonderful example of quality Q/A on this forum. Here is a used spare:


I've dealt with Yancey before...good folks.
I'm not sure if buying a used transmission is a good idea. You have no control about how well it performs - and for how long.

You have to add the considerable cost of installation (except if you can do it yourself)

But a properly built transmission shouldn't be that much more than gambling on a used one.

I'm also currently facing transmission problems - and honestly, if my transmission goes, I get a rebuilt one, not a used one (and it has 2 years warranty no mileage limit - enough times to find out any rebuild errors)
 

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2009 ML350 164.186 / 272.967 / 722.9
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Totally true re risk of used transmission. Here is a rebuild kit for $500:


(I have no experience with these guys.)

And here is a broader and historical discussion:

 

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Discussion Starter #10 (Edited)
I'm not sure if buying a used transmission is a good idea. You have no control about how well it performs - and for how long.

You have to add the considerable cost of installation (except if you can do it yourself)

But a properly built transmission shouldn't be that much more than gambling on a used one.

I'm also currently facing transmission problems - and honestly, if my transmission goes, I get a rebuilt one, not a used one (and it has 2 years warranty no mileage limit - enough times to find out any rebuild errors)
Haha, I didnt see you posted here (I just posted on your thread again). Yes, I'm thinking if I really have to go with the transmission, I'll go with a rebuilt (if it's seriously damaged inside and needs more than a overhaul kit), while I can do more and rebuild the whole thing... Rudeney also is absolutely right about certain parts getting ridiculous on cost from the extensive research/reading I've done before posting here).

On a side note I'm doing all my own work (so at least I get huge labor savings). I'm first seeing how bad this pump situation is and will be taking the transmission apart and checking the other suggestions Rudeney made. Fortunately while I have a lot of mechanical experience and the tools to do it on my own.. The one thing I might have to invest in is a better scanner or even an SDS for this car, especially if I need to recode it...

What's nice is I was at least able to get full access to the mechanics workshop manual software the Mercedes techs use, WIS.

On a side note, I'm like 99% certain this is just the conductor plate (just like yours) but I'm taking the transmission apart further to avoid other issues later, I'm just hoping this pump didn't chew everything up inside. My car is doing exactly the same thing as yours being stuck in limp mode/1st, but since it's the 07 transmission there's more things that probably need to be addressed. I'm also going to work on the valve body while it's all out. And make sure everything looks good and throughly cleck it, clean it and the solenoids etc.

I hope your transmission repair goes well, and thanks again for the suggestions. If you have any others or come across any other info you see I'm definitely interested.
 

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Assuming once I remove the transmission if it's as bad as it could be and the rebuild prices for various parts can cost a ton... Is it possible to use my existing (hopefully repaired) conductor plate in a donor/replacement transmission?
Yes, you could do that. I think you will find that if your transmission is in bad shape (but I'll bet it's not) that the price to buy a rebuild kit and new fluid pump will be not much more than a used transmission, and then you know you have a good gearbox as opposed to the dubious quality of a used one.
 

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Discussion Starter #12
Yes, you could do that. I think you will find that if your transmission is in bad shape (but I'll bet it's not) that the price to buy a rebuild kit and new fluid pump will be not much more than a used transmission, and then you know you have a good gearbox as opposed to the dubious quality of a used one.
Thanks so much for the help! And I definitely agree with you, I'm not really looking to inherit a bad used transmission etc.

I had a few things come up but should have it pulled out this weekend to know the extent. I'm really hoping it's not too bad, and I feel a bit more optimistic since seeing your other post as well. Like the magnets definitely didn't look too bad... Even before/after the flush, and I'm also glad other than the limp mode issue, it never slipped or did anything that can be more concern than the conductor plate. I just want to make sure the pump and torque converter all look good so I can have it done correctly the 1st time etc. And avoid a much bigger problem
 

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Good luck! Let us know how it goes and what you find.
 

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Discussion Starter #14
I have done a torque converter and fluid pump replacement on a 722.9.
Okay!!! Finally did it, got it out without removing the exhaust (unfortunately I didn't get to this until late Sunday), you weren't joking about tools, I'm so glad I had all of these tools from years and years of doing this type of stuff. Without the impact I'd have been done, total lifesaver. Also, all the various extensions I had to use (just like you mentioned).

So far the everythings looking decent... I'm going to use your tips here soon (thanks so much again), taking it out wasn't too bad with your advice, I just wish I had a damn vehicle lift... The Jack stands I use (and obviously use multiple as backups) are more more than safe but a lift would have been wonderful!!! That's probably the next thing I really want... (well probably the sds first, haha).

Anyway - " inspect the flex plate and replace it if it has any cracks, chipped teeth for the starter, or bends/dents on the pulse ring for the CPS." looks good!! I'm going to follow all your advice but just wanted to mention what I've seen so far is making me feel a little better. I'm thinking this thing might only need a pump, some tlc and the tips you mentioned (+ the board service).

If you can think of anything else, just let me know! I really appreciate the help, if you're ever in Austin let me know! Definitely owe you some drinks at a minimum :)

I should be able to tear into the transmission within the next few days and will update, hopefully it's good news, haha
 

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I understand wanting a lift. I did my CLK550 on jack stands, too. On that car, I used extra-large stands on the front to get enough clearance for the transmission which still had to muscle it off the jack and onto the floor to drag it out and clear the engine and frame.

One thing you might consider is replacing the the torque converter. You should be able to get a rebuilt one for $300.
 

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Discussion Starter #16
I understand wanting a lift. I did my CLK550 on jack stands, too. On that car, I used extra-large stands on the front to get enough clearance for the transmission which still had to muscle it off the jack and onto the floor to drag it out and clear the engine and frame.

One thing you might consider is replacing the the torque converter. You should be able to get a rebuilt one for $300.
Haha, exactly, that was pretty hard! I had to come out the front too, no way to go any other way. Yes, I definitely agree with you, I haven't tore it down yet, but the torque converter is a great idea on replacing so I'll do that as well. I'm basically hoping to do this one time and service the transmission as it's supposed to be done so the car can be used with minimum downtime going forward (this is the plan at least...).

Thanks again for all the help!
 

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One thing you might consider is replacing the the torque converter. You should be able to get a rebuilt one for $300.
Okay, I have to still check the pump and clutches etc but most of the transmission is looking really good early on, even the torque converter wasn't damaged like I've seen... I think I'll still replace it like you mentioned, but one quick question, other than lint free cloth/chamois leather the manual mentions was there any special cleaner/cleaning you used before using the goop for reassembly? I'm not really seeing any metal like I expected, so I'm hoping the this pump is clearly bad... I Still need to throughly look everything over but am feeling a lot better. Unfortunately this has been taking me a lot longer than normal to get back to with all the other cars I've had to fix recently. This should now go a lot faster as those are complete - other than ordering the parts and waiting for them etc..

And currently my last question... When you did the TC swap is it possible to upgrade to one that you can drain during transmission service? From what I've seen the replacements have still been sealed, but I haven't looked a lot yet.

Thanks again for everything!
 

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As for cleaning, you can use mineral spirits to loosen and clean any sludge or buildup. Microfiber cloth is good to clean up dirty oil, just use a quality brand that has been washed so there is no loose lint on it.

The TC I had on my CLK had the drain, and so did the replacement. So you have verified that yours does not have the drain? I actually thought it did, but on the W164, the bell housing access port was on the wrong side.
 

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Discussion Starter #19
As for cleaning, you can use mineral spirits to loosen and clean any sludge or buildup. Microfiber cloth is good to clean up dirty oil, just use a quality brand that has been washed so there is no loose lint on it.

The TC I had on my CLK had the drain, and so did the replacement. So you have verified that yours does not have the drain? I actually thought it did, but on the W164, the bell housing access port was on the wrong side.
Let me double check, but that's what was odd is the TC didn't look like it had one, and you're right about it being on the opposite side as far as access etc.

So I finally had time to take this more apart, really not bad, the pump looks fine... I was expecting it to have chewed up things, I can see like minimal to no wear on the B1 clutches I haven't gone over all of them but bell housing portion is fine... I'm starting to think on this car they swapped the trans and reused the old TC/conductor plate.. So now that it's apart anyway.. I might as well upgrade the pump. One question from what I'm seeing there looks like there will be some wear from the design regardless and I have seen the plate procedure that can be added, but I'm curious on these how the redesign wears against the housing.

Like how much wear is enough to replace it?

20191130_165730.jpg 20191130_165834.jpg
 

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Discussion Starter #20 (Edited)
I think the picture makes it look a bit worse, like I used the flash on my phone to get it a bit more blown out, but you don't feel grooves or major damage like I've seen from the pumps that break apart. I also think the pump should be replaced anyway as well as the TC like we discussed. Let me know what you think. Thanks again for all your time on this. Sorry this has taken me awhile to get back to...
 
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