722.908 conductor plate transmission shudder
 

Hi guys.so I have bought a 2011 e250 cdi estate with 138k full MB history and ATF done at 70k. The car has been going going into neutral while in D then stuck in D until turning it off and back on.happened few times in a few days. The codes that came up were as below. 0705 0606 1708 1709 2783. It was sometimes shuddering a little between 20-30mph for few seconds and on gentle acceleration on motorway on incline it did shudder quite bad at about 60mph. Also used to change 2nd to 3rd quite harsh like a hard jolt.Sent TCU off for testing and they said it's beyond repair. Not sure if my Torque converter or transmission is also faulty. When draining the atf was very dark and smelt burnt But it had no contaminants.

What do you think the fault is?

Thanks in advance
https://cimg6.ibsrv.net/gimg/www.mbw...4ca0e4fd23.jpg
https://cimg8.ibsrv.net/gimg/www.mbw...59fd64005b.jpg
https://cimg9.ibsrv.net/gimg/www.mbw...0b9d0e040b.jpg

Below are the pics of my oil and the panhttps://cimg9.ibsrv.net/gimg/www.mbw...ecbaefeaff.jpg
Oil colour when draining,smelt burnt
https://cimg6.ibsrv.net/gimg/www.mbw...3c58c65da0.jpg
Pan was clean but magnets were full of sticky black gunk

Get with Oda112, or search through his topics. He did a pretty extensive R&R of the valve (conductor) plate last year I think it was.

I've rebuilt domestic and a couple of Honda transmissions so take this info with a grain of salt as I've not been into the MB unit. But perhaps some info applies.

Typically the dark color comes from fiber clutch pack wear. The magnets are in place to catch metallic wear debris from gearsets and the steel rings between the fiber clutch rings. From the pic, the metallic stuff doesn't look terrible, but the fluid's pretty dark for the mileage. I assume you looked to see if there was glitter in the fluid (metallic debris). Glitter is not a good sign. Dark and smelly fluid isn't great either but you might get a second chance with that.

Bear in mind that if there's any sort of mechanical (metal) failure the TC and thermostatic trans oil cooler must be replaced. They typically can't just be flushed out because they retain debris that circulates right back into a fresh build. Shudder is more typically related to the TC - in some cases like Ford 4R70W, the condition is sometimes solved by fluid change, or change of TC solenoid. But unfortunately I can't say that's a possible fix for yours.

I "think" as an internet guess that mechanically it may still be ok but that the control or valve issue has placed a lot of slippage into the clutch packs, thus the fluid condition. I'm not rushing to say complete rebuild but the clutch packs can burn very quickly under low pressure conditions.

Others can add more or better info but I think as a possible try is to install a new or rebuilt TCU then evaluate unit operation. I suspect if the control valves were mis-functioning the unit would slip and shudder as you noted. The more it slipped the more debris that can accumulate in the valve and solenoid screens. The more that happened then the worse it drove. By changing TCU and fluid AND filter you may be able to restore driveability even with worn clutches if they aren't too bad. If you do that and it drives ok then after a few hundred miles change fluid and filter again to catch what had been trapped in TC and any metal circulation lines.

Lastly, a good shop will also ensure that the control wiring from PCM to the TCU is good, ( including connectors) has integrity and proper signal. Wouldn't be the first time a bad wire has caused a transmission shift issue.

That's all I've got, good luck!

Shuddering is most of the time caused by old fluid. I always recommend my customer to change transmission fluid at 40k miles. You will definitely need a new conductor plate. Most of the companies that repair them can only do the speed sensors only. That's why they are claiming that it its not repairable. Now, the ISM code could be caused by the malfunction of the conductor plate. So I would start with a new/reman conductor plate, new genuine filter, gasket and bolts. Drain the torque converter if it has a drain plug.

Thanks mud for the detailed reply.very helpful
I will change conductor plate first and then take it from there.the shuddering was now and again not all the time.but the gear changes sometimes at low speeds 2nd to 3rd or 1st to 2nd were very jolty..but only sometimes. It started happening for about 3 days then I stopped driving it and opened it up. Most of the time gears were smooth.

With regards to the oil it was not glittery but jus very dark brown and smelly. If my gearbox or TC were gone would my symptoms be there 100% of the time ?

MBENZTECH Thanks for the advice.yep I've got the service kit for transmission and will be ordering the new plate tomorrow from mercedes .I was quoted 258 +vat for exchange or 304 +vat for buying it. They said it's a Raman unit but the only part reused it the black casing,all the parts are brand new

As mentioned replace the conductor plate (TCU) and new fluid/filter. Then see how the unit shifts. If there are continued troubles then either the replacement TCU might have an issue or there are more significant internal troubles.
But again, always ensure control wiring is ok.

I heard replacing plate on those cars is not that easy as the part is available only from the dealers and then you have SCN coding, so you are in dealers mercy for long haul, or there is ebay guy in Bulgaria who rebuilds those plates for $400.
Than several errors on different parts usually indicate bad connection as chance that 2 or 3 valves fail at the same time are minimal.
Wash all the plugs and check wiring for damage.

UPDATE: Ok so i had my TCU replaced with a genuine with from Mercedes for £352 inc vat, a specialist fitted and programmed it me via start for 250 and the ATF kit cost me £160 for 10litres of ATF
because i left the car to drain itself after dropping the pan which released 6.5L, another 2.5L was drained by just leaving the pan off, therefore it took 9 litres of ATF so i think the TC did naturally drain.

Thank you guys for all the advice upto now! =)

Previously the car would go into limp mode and go out of gear and then i would have to restart the car and also when upshifting in D from 2nd to 3rd it would make a massive bang which would actually scare me and my wife if we were in the car.

Ok so after the programming was done and i took it for the first drive, its much better but i am still getting a medium rubbery type jolt from 2nd 3rd gear when cold only, nowhere near as bad as before, after 15mins of driving when the ATF warms up the it becomes very smooth and normal, but after leaving the car for more than 8hrs and the ATF going cold it jerks 2nd to 3rd only
i asked Mercedes and he said "its a 2011 plate with 138k miles it will have some wear on the internal parts, as long as its not jerky when warm you will be fine " , another specialist said "its your valve body that needs servicing" and another specialist said "its TC solenoid that needs replacing "

any ideas guys ?

Before replacing parts, try a shiftpoint adaptation with SDS (Star) or any other decent bidirectional tool (my Autel Ds808 can do it for example). It is normal to have a slightly perceptible shift when the tranny oil is cold, only if you'll spill your tea when it happens shall you worry.

^^Good advice, may alleviate the issues^^

In addition, something to consider. If I've understood right, the conductor plate has been replaced with an MB reman part with new TCU and new solenoids?

The conductor plate can be removed from the valve body, meaning that the VB may indeed still have debris inside of it that is affecting shift quality. There are internal spool valves and a bunch of check balls inside the VB that can be affected by general wear and debris. But it's an unknown unless it's removed and split (has a top and bottom to it). A VB can also warp slightly, causing a very slight internal leak. Many shops shy away from opening it as careless reassembly or a warped half that's not addressed can make things worse. In general though, almost any VB can be disassembled, cleaned, and inspected for straightness and free movement of all valves, then re-assembled and installed using correct torque sequence and settings.

I'm not saying that's the fix in your case, but if a reflash as Oda mentioned doesn't do the trick, there is the possibility of the VB itself needing further attention, provided the other internals are ok. But based on your fluid condition, the clutches may have enough wear to cause the cold shift jolt until there is heat buildup in the unit. I think that in this case, I would try what Oda mentioned and then just live with it rather than start tearing into things.

Oda and Mud thanks for the advice , i changed the TCU only not the solenoids. since doing the fluid change and TCU change the gearshifts are much better but 2nd to 3rd only when cold it makes a jerk under 2k revs but above 2k revs when cold it jolts. when i did drain the old fluid it did not have any contaminants visible but did smell burnt and dark brown.i will upload pics soon. the VB wasnt opened or checked but i did check all the solenoids for dirt and they were ok.

Ok so i did some code reading today out of curiousity and it showed Code 2783 - The friction power of the torque converter lock-up clutch is too high which has come up again after the TCU change and ATF flush. i called the Merc specialist and he said he changes the torque converter if this code comes up. i think this code only happens because of the jolt 2nd to 3rd when cold. i have cleared the code and will see if it comes back . the car has got the latest online software and the adaptations have been done on it when TCU was done. i asked the specialist about if it could be solenoids and he said no because there are no solenoid faults showing on star.

the car does not judder or lose speed, MPG is 34mpg local and motorways 50-55mpg which is good, no other issues, when the car is warm it doesnt jerk but you can feel the gears change but not jerks or jolts

the one thing it does do is the paddle shifts are quite slow, so CLICK....after 1.5 to 2secs the GEAR CHANGES when upshifting but no jerkiness

just a quick update- the 2783 code has come back again.. i rechecked the fluid and drained and topped up again - on cold the gear change 2nd to 3rd is much better but u feel the gear change. i put this down to the weather as its warmer
However i still have the slow gear changes, its almost like a flick in my BMW and this is like a drag from gear to gear,like a gel moving into gears, any ideas?