DRBC43AMG

I have been experiencing some small problems with my transmission which I started to describe in a thread started here: https://mbworld.org/forums/c36-amg-c...owertrain.html

Unfortunately things started to go down the drain on Monday. Sunday my wife and I managed to drive around 300km on the highway with no significant problems apart from loosing 5th gear from time to time. This was solved by stopping, cutting the engine, starting again and driving away with a light foot on the throttle going up the gears to 5th. Coming close to home and after getting off the highway, T-Rex decided to loose all gears except 3rd. OK that's not too big a problem as the torque pulls easily the vehicle.

Coming back to Monday, I went to purchase some extra axle stands as the four I have normally are used to support the Ultima which is in the build process. Driving up the slip road to enter the highway, I accelerated normally and the gears changed up to 2nd and nothing more. So I pulled to the side and tried the engine stop/start procedure. Only gear I could get was 1st So I managed to crawl back home slowly, then put T-Rex to bed, waiting for the vehicle to cool down.

I spent the afternoon trawling the net and researching 722.6 transmission problems and solutions. So this is what I am going to be doing and the parts to be changed, so I thought it could be a good idea to document the procedure.

- Conductor plate
- Harness plug
- Filter
- Oil pan gasket
- ATF Fuchs Titan 3353 Dexron III

In my research I learned that some extra parts should also be changed as this will improve and sharpen gear changes and overall transmission operation. I thus ordered from the USA the folowing:

- Sonnax 68942-05K Overlap Control Valve Sleeve Kit
- Sonnax 68942-01 Regulating Pressure Control Valve Spring

Below is a pdf file containing the diagram of the transmission's main control unit with identification of the different kits available through Sonnax. Specialists say that the Sonnax products and parts are higher quality that the MB ones, that's when you can find them. It seems that some parts are no longer available through the dealerships.

More news tomorrow

PJmak

Watch this guy also. Very good source of information

DRBC43AMG

Yeah, I have seen plenty of his videos. Good technical information, but I find the guy talks a bit too much... There is another Youtuber under the name Fubabox who also does plenty of more down to earth repairs specifically on the w202 which is more in line with our queens

DutchC54

i woud suggest to also replace this part.
https://mbworld.org/forums/c36-amg-c...ml#post6775111

the pink seal might leak at some point.
now that u will remove the oilpan and replace the filter its just a little more work to do so.

DRBC43AMG

OK thanks. I will look into this also.

DRBC43AMG

Yesterday I removed the pan and filter. Then unplugged the harness plug and with some trepidation looked inside..... Bone dry, so that's great news! The two O rings looked a bit soft, so it could have started to leak in the not too distant future. The filter was also clean and at the bottom of the sump and around the magnet there was some metal gunk. No bronze filings around either. The ATF still had a deep reddish color even if it was chocolate brown and smelled a bit burned. Cleaned everything with my work bench parts washer and replaced the sump plug with a new copper crush washer and screwed it back in the pan.

Started removing the bolts holding the valve body and managed to remove all except one. I thought they were on rather tight, so I prayed and held my breath each time I broke each bolt's seal. It worked great except for one in which the Torx head was buggered So it will be out with the drill and then an screw in extractor bit. I just need to be careful not to get any flying bits of metal too close to the valve body. Fingers crossed this will work and I can remove the unit.

DRBC43AMG

This morning the Postman delivered a nice big parcel with the new conductor plate. I can now proceed with the removal of the valve body from the transmission.

Confronted with that buggered bolt head, I drilled a 1cm deep hole with a new HSS 4mm drill bit into the centre of the Torx bolt and then tightened an extractor bit and bingo the bolt freed up As several of the bolts show some damage in the Torx head area, I ordered 10 new bolts at the local dealer.

After unscrewing the last 2 bolts holding the valve body, I lowered the unit (a bit heavy when working on your back under the vehicle) onto a MacDonalds food tray I had lying around the workshop. Hmm I wonder how it arrived to my workshop... The valve body fits perfectly onto the tray and the remaining ATF can seep out of all the holes and crevices without dripping all over the workbench.

I then unscrewed and pulled out the 6 valve bodies and put everything to the side after wiping everything with kitchen paper tissues. Lastly, I covered the parts with some clean paper tissues and supported the valve body up on an angle to empty the remaining ATF. I should note that everything I removed was oily with ATF, but I found absolutely no gunk or residues on any of the parts.

Next job, wait for the delivery next week some time of the two Sonnax kits which are arriving from the USA and then rebuild the valve unit. I may check and change the two O rings found on each of the valves for peace of mind as everything is now accessible. Cleanliness is vital from now on and until everything is rebuilt, assembled and back in the transmission.

Stay tuned for further details next week

DRBC43AMG

Picked up 10 nice and new M6 Torx headed bolts this morning which will be used when reassembling the valve unit.

cm60k

You doing great job Daniel,

did you check the "Pressure regulator spring",,

when it's bent or broken, it will cause slips between shift points:-

http://www.benzworld.org/forums/w210...placement.html

,,ZAYED,,

DRBC43AMG

Yes, new Sonnax one ordered and will be changed. I havn't got round checking to see if the current one is intact or not. I'll let you know next week. I'm leaving for a couple of days to see friends in Locarno.

DRBC43AMG

Swiss Post informed me that my Sonnax kit should be delivered tomorrow

PSDCampervan

Looks like you putting in some Strong work so far!

https://www.youtube.com/user/questioning3/videos
https://www.youtube.com/user/MBOwnersClub/videos
A couple YouTube channels worth subscribing to if haven't already. Both showcase & feature teardown & repair of MB 722.6 & others. That 2nd one has been uploading a new video every 5-10 minutes for like a solid week now! All MB factory shop training videos on various vehicles!! It's the motherload

DRBC43AMG

Excellent source of videos. I hadn't seen them yet. Thanks

DRBC43AMG

I have finally all the parts that were ordered. Back to the workshop today

I'll also be doing a complete brake fluid flush as it's been two years since the last time I did this. My Motive pressure bleeder will be put to good use

DRBC43AMG

Valve body ready for reinstallation with new Sonnax Overlap Control Valve Sleeves and electronic control unit.

It seems that the valve body has been changed previously as it has a 06/02 stamp in the casting. There is also an date etching somewhere on the side, but I haven't checked it out yet. Could the transmission have been changed in the past with bushing or other problems?

Also the ID# on the casting R1402773701. A web search came up with a match with a 2006 Dodge Van Sprinter 2500 valve body! The Sonnax spring (the one in the middle in the photo below to replace the one on the right) does not fit either as this is a later than 99' valve body. I didn't know this when I ordered the parts.

The mystery thickens...

DRBC43AMG

Searched around the valve body before reinstalling and found a date etched on the side: 16.03.00 so it seems that the valve body was changed after the 99' vehicle manufacturing date. I don't know if the transmission was also changed or rebuilt if it experienced the disastrous failures those 722.631 transmissions had in the early days.

The mystery remains...

cm60k

Yeah sure, this is the second updated V/B,,

the first one comes with "140 04 06", the second one with "140 06 06", and the last one with "211 00 06"..

,,ZAYED,,

DRBC43AMG

So everything is back in place.

After careful measurement of the old oil (see photo ) which I recovered and will be tipped into the appropriate local mineral oil disposal container, I removed and replaced 4,9lt of Fuchs Titan 3353 Dexron III ATF.

Next job tomorrow will be to lower the 43 on the ground, then take her on a test drive to get everything hot and see that the transmission works, check for leaks (shouldn't be any, but one never knows and I hope not...) and do a final measurement using a MB workshop dip stick.

As I had the error code P0715 in the system, I probably will be needing to get my Carsoft Software program connected to read and erase the error code. You can't use a regular code scanner, just the Star or a clone software.

Before finishing the job on my transmission, I checked the ID# on the bell housing: R210 271 08 01. I checked in the EPC but the part is unknown
Zayed if you can help out??

cm60k

"R 210 271 08 01", is the correct part #, for almost all 722.6xxxx,

then MB replace it with "A 210 271 18 01"

and (R) refers to the first production of "ZF/GmbH"..

,,ZAYED,,

DRBC43AMG

Thanks bro, guess I learn something new every day

KJI3jflarryfe93

how much did Sonax parts cost you in total with shipping?
i hope you get better shifiting with these parts

where's the link for Sonax parts?
are they spezialized for MB transmissions?
parts you bought are they for improving the longevity of 722.631 tranny?

DRBC43AMG

Sonnax site is here: http://www.sonnax.com/

No direct sales to individuals, so you need to go through a local rep or buy on e-bay. In Sweden you have these guys: http://www.sonnax.com/distributors/84
My valve sleeve kit was purchased (price indicated) on e-bay with these people: http://www.ebay.com/itm/Sonnax-68942-05K-Overlap-Control-Valve-Sleeve-Kit-Fits-722-6-Mercedes-Benz-Trans-/262047308343?vxp=mtr&hash=item3d033c9a37Transport was a further $20 approx.
The second Sonnax kit I purchased with the local rep in Geneva. Finally didn't use it as I have the later valve body as explained in my posts in this thread.

DRBC43AMG

A last post to finish this 722.6 repair and maintenance thread.

So finally placed T-Rex back on her wheels and decided to take her out for a test drive. I ended up only going to the end of the drive and back. The transmission was blocked in one gear and wouldn't shift further. Thankfully reverse also worked so I could get back into the workshop. The dreaded P0715 code is stopping the transmission working normally. No normal OBD scanner is capable of erasing and setting the transmission back to normal, only with the MB STAR diagnostic system can you do it.

Three years ago I purchased in Belgium a STAR clone called Carsoft. It cost around 200Euros and comes with everything (software and hardware). Check the site here: http://www.carsoft.com/
and this is the software package I'm using: http://www.carsoft.com/single-brand/carsoft-mercedes-v12-system.html
I had never got around to using it, as my old laptop didn't like this software. As I have a new laptop since a couple of months, the software now works perfectly. After connecting all the electrical plugs, everything started talking in the same digital language.

I did a full diagnostic scan which took a good 20-30 minutes and the results showed 2 red (important) error codes. One linked to the P0715 transmission speed sensor in the electronic conductor plate, the second with the ABS/EPS system. The ABS/EBS is probably due to the brake fluid flush and bleed I did the other day. Going then to the error codes individually, I erased the two and redid a diagnostic. All clear and green to go.

Went for a quite test drive in the neighbourhood to get everything up to operating temperatures and not to far, in case I had problems…

BINGO, the transmission now changes all the 5 gears perfectly and its super smooth, both changing up and down the ratios. After around 20 minutes drive (outside temp is 30°c so things get hot quickly), I came back to the workshop and measured the ATF level. I added 0,5lt and the level is now perfectly in the middle of the 80°c range on the workshop dipstick.

I just need to get the air-box back on but that will be later as the engine is super hot. I must say it does have a nice deep throaty intake noise without the air-box, but no way am I keeping it like this.

PJmak

Its a good time to unhook your battery for 15 minutes so the ecus reset then go for a good long drive.

Glad to hear everything worked out

DRBC43AMG

I guess the full diagnosis and code erasion also cleaned out the ecus