PeachParts Mercedes-Benz Forum - 722.6 Transmission Refresh. DIY and questions.

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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

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.

I have it right at the middle of the 80c. I think i need to add half a liter to get to the top of it.
I'll have 7 liters in at that point. Not bad. I didn't drain the TC.

Hmmm... Generally about half (4 liters) drains from the transmission and about 4 liters from the torque convertor. I guess YMMV :D.

I read 4-5 from the quick service and about 9 for a complete exchange :)
I'm guilty of cranking the engine with the tranny pan out (and injection fuses removed) to spin the TC and drain some more. Not sure if that helped that much, but i have 6.5 empty bottles and the level at mid 80C

This is from some online sources
For Mercedes models with 722.6XX electronic 5-speed automatic transmissions.
Up to 9 liters per car with complete drain, 4.5 - 5.0 liters on service flush only.

Concerning the fluid and level, here is a link to a post here that is a copy of a handout I received at 722.6 MB school, it is informative and in a rare moment they even added some humor to it:

http://www.peachparts.com/shopforum/702285-post8.html

Here's an update. I just got a pm from someone on the forum and thought I'd share this offer.

My transmission is now probably the bast part of the car. And I haven't had any issues with it so far.
I may have all the parts you need to get your valve body refreshed.

I actually have a 722.6 valve body that is refreshed. So I can send that to you assembled and it would just be a swap and I assume a few hours of work.

If you decide to get my assembly, this is what you would get.

1. Used Cleaned valve body
2. New sonnax valve overlap kit installed
3. New pressure spring installed
4. Tested solenoids and 1-2 gear solenoids swapped with 4-5 gear solenoids. All solenoids tested for resistance.
5. New conductor plate
6. New harness adapter for the conductor plate
7. Gasket and filter kit
8. Dipstick tool
9. Lock pin for the filler tube
10. Washer for the drain bolt in the oil pan.
11. Fuchs transmission fluid - 6 liters (you may need up to 9 liters if you decide to drain the torque converter. I didn't have the drain bolt on mine)
12. Plastic covers for the solenoids
13. Magnet for the oil pan

And that would be 500$ shipped.

The reason the price is high is because of the valve body. They sell used for 300 on ebay.

If you decide to rebuild your own valve body, than everything but option 1 in the list will be 350 $

If your gears are slipping than the refreshed valve body will not fix the issue.

Also, you may have the transmission trouble codes in the module that need to be erased. You'd need the MBstar tool to clean the error codes and reset the adaptations. The tool will also help you check the transmission fluid level since it's very sensitive to the temperature.

I have the tool and could rent it to you if you leave a deposit. You can give me remote access to your laptop and I'll guide you. The deposit will be 400 and I'll charge you 20 $ a day to rent it.

I currently have 1 unit for w140 and 1 for w210

Nice thread. Is there a trick to changing out the adapter plug? Is it just pushed into the transmission? Or screwed in? Or do you have to remove valve body?

My plug was full of oil. But lucky the tcm was dry inside.

Thanks

There is a machine screw in the middle of the plug. It is fairly small, hex head probably in the 8mm range IIRC. The screw is screwing in to the conductor plate inside the trans. But yes it is easy just loosen/remove that screw and it (the connector) will pull out. Replace using new o rings and also on the connector. easy peasey. You may lose a little fluid, be sure to check fluid level correctly as noted in this thread, especially if it has been leaking (on to the ground, not just sloppy in the connector).

Quote:

Originally Posted by MEPEH (Post 3023448)

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.

Nice work on the Sonnax overlap kit and swapping the solenoids around. That sounded like a briliant idea ;) I almost wish I would have done more of the Sonnax parts that didn't require bore rework when I had mine apart namely the TCC Damper Valve and Sleeve kit: 68942-23K. I'm sure I will have this car for quite a while so perhaps it still can be done in the future.

Just found and read through this excellent thread.
A few days ago, my 99' C43 (277'000 km) started playing up like loosing fifth gear, then reverse. Gear changes were harsh and this morning it lost all gears except 1st and reverse. I figured the conductor plate was probably the culprit because the only code stored was a P0715 which is a Transmission Input/Turbine Speed Sensor Circuit Malfunction.

I ordered a new conductor from a parts supplier in Germany (I live in Switzerland), and also the Sonnax Overlap Control Valve Sleeve Kit #68942-05K. Unfortunately that's going to take 2 weeks to get here. I purchased the gasket, filter, crush washer for sump bolt, not forgetting the wiring harness plug with O rings even if the one on the transmission is bone try.

I just need to order new O rings to use when reinstalling the solenoids.

Plenty of Fuchs Titan ATF already in stock together with a dip stick, so guess I'm ready to roll.

Anybody see anything else to add?

The next most important thing to your conductor plate is the pressure regulation spring. Here is USA it is not sold by Mercedes any more, but by Sonnax... The spring will not cause limp mode, but they break...

722.6 - Sonnax

Regulating Pressure Control Valve Spring - 68942-01 - Sonnax

The 2-3 shift valve sometimes fits very tight, so some times it needs to be sanded down a bit...

Martin