722.6 Transmission Refresh. DIY and questions.
 

Ok. So here's my next project.
I have a 1998 CL500 with about 200k miles on the original transmission.
The previous owner "forgot to mention" that the tranny was quitting and i inherited a surprise on my way back.

First symptoms:
A few hard shifts 2-3 gear and it went into limp mode.
Stuck in 3rd gear. CEL on with generic p0700
(TCU malfunction)
Also Trouble codes for speed sensor.

Opened the coffin box and discovered oil.
Replaced the harness connector + TCU
Dried the connectors and everything was great for the next 200 miles.

Second symptoms:
2 more hard shifts 2-3 and transmission gets stuck in 3rd.
No check engine light until it goes in second gear limp mode.
CEL on with p0715. Speed sensor again.

This is what i just ordered and plan to replace.
1 Conductor Plate
http://ecx.images-amazon.com/images/...500_AA300_.jpg
2 Pressure regulator spring 2-3 gear
http://europeantransmissionscom.x-sh...ype=T&id=16396
3 Sonnax Mercedes 722.6 Overlap valve sleeve kit.
http://a248.e.akamai.net/origin-cdn....jpg?1314184854
4 Fluid Fuchs titan atf 3353 (They make the fluid for Mercedes. Too much controversy with other oils so i'll stick to what's been tested)
http://www.lubricants.com/images/lub...TANATF3353.jpg
5 Pan Gasket and fluid Filter
http://htsmall.ecklersmbzparts.com/a...u/P27-077K.jpg
6 Dipstick
http://www.denlorstools.com/shop/images/M_7226_L.JPG
7 Washer for the drain nut
http://i1266.photobucket.com/albums/...m/01984ccf.jpg
8 Lock Pin for the filler tube
http://www.everythingbenz.com/prodim...num=1409910055
9. Also PLEASE don't forget about the harness connector. (I replaced mine a few days ago and got rid of all the oil that leaked into the TCU)
http://www.autoshoppingcenter.com/tr...ilter_plug.jpg


Also plan to order carsoft Today to reset the codes. ( Or maybe C3 or C4 ?)

I doubt i'll get all my parts before the week ends so plan to do it next weekend.

What did i miss ?

P.S: I'm ordering 2-3 pieces of each. So if anyone wants a "kit" to refresh the 722.6 - PM me for details.

Compression washer (seals) for the drain plugs on the transmission and convertor. Very cheap at dealer. Also, a 'dipstick tool' to set fluid level correctly - very important. Foolish to do service without it. Also, replacement plastic lock tab on cap for dipstick tube. Cap may stay on without it if o-ring inside is good. Some people have reported it came off while driving.

Thanks. Ordered those too.
Will edit my post to include in the list

Tension spring for 2-3 gear.

I'm guessing this a valve body part since you are not pulling the trans. Is this a Mercedes or aftermarket part? Numbers?

Everyone recommends replacing it. It's a 2$ item and saves a lot.
It will smooth the shifting from 2-3rd gear (since these are the most used)
It's a DIY and this is where you can find details
722.6 Pressure regulator spring replacement - Benzworld.org - Mercedes-Benz Discussion Forum

Shouldn't take more then an hour if that's the only procedure you do.
No need to pull the tranny. Just the pan

By the way. I purchased a couple of them. If anyone is interested PM me.
Should get them early next week. Will try to take as many photos when i work on mine

Another question, was your speedo still working even with the 0715 speed sensor code? I've got a 97 E320 parts car that stays in 2nd limp / CEL on. One time after start up it did shift fine but from the next key cycle it went into limp.

Another oddity is when the trans is stuck in 2nd,the dash mounted high beam indicator is on and there is a warning message on the driver info display. ( it is ABS or ASR , don't remember. ) The speedo works through all of this so it either gets a speed signal from the ABS sensors or the trans output shaft speed sensor is intermittent.

Somewhere I came across some info that these cars used a front ABS sensor to drive the speedo.

Correct. Fron ABS Sensor dictates vehicle speed for the dash and ECU

The speed sensor P0715 is for transmission control purposes.

PLEASE REMEMBER: Once the Limp Mode 2nd Gear is engaged, the Trouble Code will stay in the Transmission Module until erased with a MB STar Tool.

Generic OBD Scanners WILL NOT ERASE TRANSMISSION CODES
Disconnecting Battery, Sleeping in the car or dancing around it will not help either

(Sorry for the caps, i've been researching this topic a lot and people rarely mention it. Lots of people get convinced to get a new TCU for 800$ rather then erase the trouble code in the original one)

Magnetic pad for in oil pan, i don't think your 1998 will have it, I have one around here I can grab the PN off of if you need it.

The new conductor plate should come with the covers for the solenoids, be sure to install these, they are NOT just for shipping purposes, they were added in later in production and should be there, again your 1998 might not have the covers originally. If you don't have the covers with the new conductor plate I would get them before putting the valve body back in.

Yes, please. Can i have the part number for the magnets ?
Everyone mentions it but i haven't found any p/n

Appreciate your help

Mepeh,

Good job on your analysis, I would do a fluid exchange on the whole transmission. You'll use four to five gallons of fluid, so you get 100% of the fluid out not 80 to 90% with a torque converter change. I did one on the same year vehicle a month a go. I would change out all the solenoid o-rings, each solenoid has two o-ring's as these o-rings will be disturbed when the conductor plate is replaced, but you may have to go aftermarket with those. Clean out the filters on the two regulating solenoids, and swap out upper shift solenoids with the lower ones.

Here is cheaper source for the fluid.

item detail

Best of luck,

Martin

ohhh, Inspect the Pressure regulating spring on the valve body. I'd even replace it, Sonnax and Mercedes sell it.

Martin

Thanks. This part is on the list. :)

I ordered 20 liters of FUCHS fluid. I'll just use as much as it takes and sell the rest.
I've read a lot of different opinion about the ATF and, I'm already saving money by not buying it from the dealer, so i'll just go with FUCHS.
May be next time i'll try Shell.

I've read about swapping the lower solenoids with the upper ones.
Do you know what the resistance should be ? I know you can measure and see if it's within acceptable range.
Also, where do i get the seals for the solenoids from ?

Now my biggest dilemma is:

How do i reset the Trouble Codes when I'm done ?

Carsoft 7.4 is only 85$ but i'm afraid i'll curse everyone trying to make it work and will have limited access to the rest of the modules on the car.

Star C4 is overkill in my situation @ 800$ for the Kit

Star C3 seems reasonable at about 350$, but i haven't found a seller i can trust yet.

(I used to be a bosch certified technician and have experience with good scan tools and german cars. I just switched to Mercedes after owning pretty much all the BMW models up to 2006. I have the latest BMW ICOM that costed me about 4k and used to do everything related to warning lights and electronic malfunctions)

Now i'm trying to find something for Mercedes that would give me similar performance without forgetting i'm just a DIYer

It sounds like you've covered the internals, but while you're there ...
with 200k miles, the flex disc and shifter linkage bushings may be due for replacement.

Mepeh,

The dealer fluid, stay away from it as it rated for 722.9 trannies and 722.6 owners complained of accelerated wear to failure in a year or two, so even if the stuff is a penny a quart, walk away...

I saw your post on benzworld, and I replied to it about the scan tools. I too am on the same fence, but I have not pulled the trigger to buy it. I would buy it from these guys, and one great member there made it work with no problems.

obd-club

The original thread:

Who has their own MB Star / DAS C3 Diagnostic kit? Need some pointers.. - Benzworld.org - Mercedes-Benz Discussion Forum

Here is thread on how to test the solenoids, and I believe they are about 50 ohms or so.

S420 transmission trouble - Benzworld.org - Mercedes-Benz Discussion Forum

Here is a step by step on fluid exchange on W140 post no 6

What is my transmission? Fluid? - Benzworld.org - Mercedes-Benz Discussion Forum

The seals, I have to find the link on my other computer. For the life of me I cannot remember. I know DACCO transmissions may have it and precision international will defiantly have them. Here is the DACCO one:

DACCO Transmission Parts | America's Largest Remanufacturer of Torque Converters

722.6 diagram:

Automatic Transmission Parts Catalog - DACCO, Inc.

Let me check my other computer and Mercedes EPC, give me a day or two.

Martin

That's great help. Thanks
I just placed my order on obd club for a C3. It's confusing on their site how they call same models with different names. I would prefer to go through ebay in these cases, but the only guys selling there have max 5 feedbacks. And it's something you will definitely need support for. And Vivi replied to my emails pretty quick and advised which one exactly to get.

I'm afraid Carsoft will be more headache then the MB Star C3. I've heard of issues with C4 due to it's wireless connectivity. I have the wireless option on my BMW tools and it's much slower on wireless then cable.

Thanks for the links, will have to look into that and order.

I know the flex disk was recently replaced, will have to take a look at the bushings

Solenoid Covers. Are you talking about 459 and 459B in this diagram ?
http://www.daccoinc.com/pdfs/catalogs/MERCEDES_722-6.pdf

Received the first packages today.
Placed the order yesterday

I think this is the best part of the hobby. Buying parts and seeing them on the porch delivered. Buying wheels must be a pleasure for everyone here.
The second best part is selling your old parts and getting more then you paid for the new replacements.

http://i1266.photobucket.com/albums/...ps5944ef8b.jpg
http://i1266.photobucket.com/albums/...ps1dbd2ce1.jpg

http://i1266.photobucket.com/albums/...ps15d7a652.jpg

Have to mention 3 of the 20 bottles got damaged and leaked fluid in the box.
In no way i want to make bad advertising to the company. They have been great all the time. Never missed a package. Always receive the next day.
Will see how CS will handle the issue

Martin, what does MB have available for the 722.6 transmission if it is not the 134 fluid they currently sell for the 722.9?

Conductor Plate. 1402701161
Incorporates the Plunger, the circuit board to the actuators, the speed sensor and the connector that you see leaking on the outside through the infamous seals

http://i1266.photobucket.com/albums/...pscd97261d.jpg
http://i1266.photobucket.com/albums/...psee1946b1.jpg
http://i1266.photobucket.com/albums/...ps3ec7540f.jpg
http://i1266.photobucket.com/albums/...psb9848060.jpg

MB does not sell the old 236.10 fluid....(001-989-23-03-10)
ONLY 722.9 fluid 236.14 --> 001-989-68-03-13
They STATE its backward compatible, but the fluid properties are different. The 236.10 is a variant of Dex III that is more compatible with the electronic components inside. 236.14 is much further away from Dex III.

My recommendation -- do not use it.

Go with the OP's choice of Titan 134, or Shell 134 found at Ryder Fleet Products . com
They have it listed as Penzoil, but its Shell and its perfect for 722.6's....12qt's for $70. Win win.

Changed the CLK320's at 103k, original fluid in it, no issues shifts great going on 10k miles now.

Others say Walley world Maxlife Dex III is fine and no issues, but no information from anybody going over 100k with it, so not worth the risk to save $30 per change. Intervals every 60k should be fine.

Yes those 459 & 459b are the covers, see if they are maybe on your solenoids already in the trans, I don't see them with the new part, they used to include them with it.

Magnet:
2202710098

pic (above guys finger in pic)
http://www.benzworld.org/forums/atta...y-img_3067.jpg

Glad to find that out about the fluid in regards to the 722.6.

Thanks Gilly. The only place that sells the magnet online wants 11$ for shipping. I guess i'll just stop by the dealer and buy it

Regarding Penzoil/Shell Oils, please someone post a link where i could get it
Ryder doesn't sell it anymore, and the link everyone posts to the Shell oil, well that requires a customer code now that is probably provided to wholesalers only.
I'm still waiting for them to get back to me with instructions on how to obtain it

Wolfs Head transmission fluid

Anyone ever try this stuff?

Just because it states it is 236.10, it does not mean it is APPROVED by MB for 236.10 standards. There are plenty of high quality fluids out there that are MB approved. The use of anything else would either be worse, or at the very best, have a negligible difference that will more than likely go unnoticed.
Some say its marketing so it forces you to purchase the product from companies who are financially affiliated to MB, but at the end of the day, its up the user if they want to save a few bucks on a multi-thousand dollar transmission.

When it comes to regular oil, i can play around and try different brands.
When it comes to Mercedes Transmission Fluid, Mercedes SLS Fluid, i'll go with what was tested and recommended mostly on the forums.

Mercedes Label, Fuchs or if you are on a really tight budget, get the Shell (if you can find a retailer). Too bad there's no Mobil Fluids for transmission, i would definitely trust that brand

Mepeh,

Go to find out what the Chrysler gang is using for the NIAG(same as a 722.6) transmission?

I just stuffed my $1000 S500 with Valvoline MAX-Life tranny fluid approved for NIAG transmission. Any transmission fluid would have worked including water for my S500. The tranny fluid was never changed in all the 185k miles. Tranny works great..

I'll have to poke around the jeep forums for fluid.

Martin

I use Mobil One syn. ATF works fine

I called the dealer and inquired about using the MB 134 ATF in the 722.6 transmissions and that is what they use. Wonder if they have seen an increased failure rate after putting this fluid in these transmissions.

The Fuchs 236.10 ATF is still available online. Pelican Parts has the 4 liter bottle for less than $10/l with free shipping(?). You can also get the MB labelled 1 liter containers for a few dollars more. Probably subject to whats left on the shelf.

http://i1266.photobucket.com/albums/...psf9ff8817.jpg

found my problem. Cracked speed sensors :)

Took everything apart and about to reinstall the new parts.
No magnet in the pan and no covers on the solenoids.

Copy that, will get on it.

All in all, the task was pretty easy and minimal tools were required.

So far, I replaced:
Conductor Plate
Pressure Spring
Sonnax Overhaul Valve Kit (all 3 Valves)
And Swapped 4-5 Solenoids with 2-3


The big plastic caps that i have missing on the conductor plate are to keep the metal shavings away from the solenoid contact points.
Waiting for the Magnet, Conductor Plate Covers (Thanks Gilly)

In my search for solenoids, i acquired 10 solenoids from a W210 (different part number from what i have) So if anyone wants them i can sell them at 20$ a piece. I'll get the part number if someone is interested.

http://www.startekinfo.com/manual/volumes/cd1/2_3/p23.pdf

Here's a nice pdf on all the resistance for the solenoids. I know I've been looking for this info for a while

You can check the resistance at the TCU connector, no need to pull the pan

I'm getting a bit cornfused.

I bought some MBZ ATF from an ebay seller for $12/ltr. Part number is A001989680313.
The front of the bottle says "ATF 134". On the back label is "Sheet 236.14".

I have 1999 and 2000 C280 and 2000 C230K. So I should NOT use this fluid in these cars?

BTW, went by a NAPA store for some Zerex G05, and they had Febi ATF, back label had 236.10, for $11.50/ltr.

Got the plastic covers for the conductor plate and the magnet for the pan today :) THANKS GILLY :)

I only wanted to torque the valve body to the transmission and finish the rest tomorrow. (Can't find my 7mm Socket for the conductor plate plug adapter).
The plastic covers cover the solenoids pretty well and i think they will do a good job at keeping the metal fillings away from the contact points.

Not sure where the magnet needs to go. I assume it doesn't matter as long as it's on the flat side of the pan, away from the filter

Also need to mention that the fluid i got out of the transmission looked very healthy, except that it was dark. And my transmission doesn't have the drain bolt for the torque converter.

Please post your comments about C3 diagnostic tool when you've used it. Thanks.

There's good news and bad news :)

The good news is that it was delivered super fast (next day after shipping from hong kong to LA). I was able to install on my laptop without issues. Boots a lot quicker than the BMW applications i have. DAS connected to the car and was able to diagnose and reset. The quality of the multiplexer is great and cables are "military" grade :)

Bad news is that besides DAS, i got Xentry, WIS, ASRA , EPC, Finder and MB Media applications.

Xentry errors on startup and says the registration key is invalid.

I can work on my car with DAS only, but i was expecting everything to work right. The seller i purchased the system from is on my skype list. So we tried to troubleshoot what was wrong last Friday (Saturday in China)
He sent me a few different keys (253 characters long that can't be pasted, you need to manually input them) So after i spent the rest of the night till about 1am local, we decided he will call the "factory" and get a new key for the Xentry.

It's been a week and nothing. I plan on opening a chargeback with my credit card company. In fact, i left him alone all week and didn't say anything just to see what kind of support i would get. So today, i should get the refund (or whatever it takes with the bank to process).

I will be done with the transmission today, and i know i have to delete the transmission errors and i'll be able to achieve that with DAS. But i'm not 100% satisfied.

Sorry to here that. I was hoping for better news since I was considering buying one. Your experience is somewhat the same as the $99 multiplexer which included a pirated copy of Carsoft 7.4. Oh well back to the drawing board...

My Transmission refresh project is completed.

It shifts like no other mercedes i've ever owned. Going in reverse is 0 shake. Shifting from 1st -2nd is just unbelievable. I mean i need to observe the needle on the tachometer to realize that it actually shifts.

I think swapping the solenoids and overlap valves did the trick.
My pressure spring looked great and i only replaced it for the peace of mind. It looked and felt exactly like the new one.

I've been thinking about taking pictures as i go, but it's so simple and straight forward that pictures are really unnecessary. I think it's as easy as inspecting the crankshaft bearings. It requires attention but it's all about taking the oil pan out :)

I did it in my own garage on Jackstands and had good lightening
The Valve Body is a little heavy, i think about 12lbs. So if you're working under the car by yourself, you need to use the elbow to support it and remove the bolts slowly.

The other thing to mention is don't place the magnet under the filter, it will attract the filter and you'll have to reposition again.

For those that have the 2nd Gear Limp Mode, remember that you need to clear the codes in the EGS after you completed this refresh. Otherwise you'll think that your work was in vain.

I used 5.5 liters of Fluid and i'll check the level tomorrow to make sure it's fine.

Took it to the freeway and was cruising at 75mph @ ~1900rpms :)
Reverse or any other gear ingage is just amazing. I was so excited i took my wife for a ride
(of course she didn't get it and only complained that i didn't recycle the bottles i have in the trunk)

If anyone has any questions, feel free to ask.

First Part - removing the valve body

1. Disconnect Battery (f*ck it, i decided to listen to the radio as i work)
2. Use a Torx tool to remove the Drain Bolt.
3. Drain the fluid. (It really doesn't matter if your engine is cold or warm, I prefer working on a cold engine)
4. Remove the Metal Cover that protects the Wiring Harness Adapter - 1 Torx Bolt (Same as the drain Bolt)
5. Unplug the Wiring Harness (Rotate the 'white' plastic clip counter clock wise and the connector will come out)
6. Remove the Harness Adapter - You need a 7mm socket to unscrew the bolt that's deep inside the adapter. You will need to replace this adapter due to the common worn seals so it will help you get an idea where the bolt is (it's impossible to see it under the car and there's a risk you'll damage the pins if you have no clue what you're looking for)
7. Remove all the bolts for the oil pan - Watch out for remainings of fluid coming out of the loose pan
8. Remove the Valve Body - Same Torx tool as the pan and drain bolt. - The volve body is not very light so use extra care when you do it. - Again, watch for fluid coming down in your eyes.
9. After you removed the Valve Body, You will place it on your work bench. And this is where the fun begins.

Second Part - refreshing the Valve Body
1. Remove the 3 bolts that hold the solenoid clips - same torx as all the other bolts (love it)
2. Remove the solenoids - just shake them back and forth and they will come out
3. Remove the Conductor Plate - there's a fe clips on the side that hold it - don't be afraid to break them, you will have to install a new conductor plate either way
4. Ater the conductor plate was removed, you'll have the bare valve body to replace the pressure spring and the overlap valves

The master overlap valve kit comes with instructions and pictures so i won't describe that
here's a pictre
http://a248.e.akamai.net/origin-cdn....6894205K-2.jpg

The Valve Pressure Spring is under one of the metal plates that needs to come out - very easy
http://www.makcotransmissionparts.co...40-12345-t.jpg

Remember to check the Solenoids for resistance and see if they match the specifications
It is advisable to swap the lower 2 solenoids (2-3 gear) with the upper solenoids (4-5) this way you'll have less worn solenoids where you need them the most.

Reinstalling is the reverse of the above, except you need to be careful to match the shifter lever with the plastic clip on the valve body.

I didn't have the drain bolt on the torque converter. So i filled with 5.5 liters of Fuchs Fluid.

Thank you for sharing your experience. Glad the Sonnax parts worked well.

Martin

Yes, Sonnax worked great, i was a little apprehensive since their new valves look different than the stock ones. They have the o-rings on them that will probably help them last forever. My current valves had scuffs on them and looked worse than the new Sonnax. They made it very easy, marking each of the 3 valves with marks so you don't mess it up.

All the parts i used on this transmission, i purchased in multiple quantities so PM me if anyone is interested to do the same project. I could make them in a complete kit so you have everything you need to complete this job.

I have access to WIS and can paste the images of the step by step guide made by Mercedes

Here are my old overlap valves. Pretty worn on the left ones
http://i1266.photobucket.com/albums/...ps7813e7c3.jpg
http://i1266.photobucket.com/albums/...psb817f240.jpg

MB Star shows the Torques of the engine live :)
http://i1266.photobucket.com/albums/...psf4fc621c.jpg
http://i1266.photobucket.com/albums/...ps58c4cf8d.jpg


And this is the Transmission Fluid Condition Reset

http://i1266.photobucket.com/albums/...psdabd2b81.jpg


Here's the Dipstick. There's confusion on it. It doesn't have to go all the way in. If it stops than stop pushing. I made a 'mark' where it stops for reference

http://i1266.photobucket.com/albums/...ps3e9332d2.jpg

http://i1266.photobucket.com/albums/...ps795c20ff.jpg

http://i1266.photobucket.com/albums/...ps6a13de0d.jpg

The difference between a running engine fluid check and a shut off is about a liter.
So check at 80C with engine running to get an accurate reading

Right, the stick is a tool and is not intended to stay in. It is used for all the 722.6's, the cars will have different length dipstick tubes, so they measure off the bottom of the pan. You have the advantage of having the shop computer which will interface with the ETC so you can just read the temp off the way you're supposed to do it, it's pretty critical to get the measurement correct. Without that, the home mechanics have to read the temp of the pan itself, which if you ask me is no way to do it accurately.
Try getting the level right at the top mark on the 80 degree range, per MB.

+1 on accurate level. If you overfill you should drain some out.