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Advice/best guess for 722.9 transmission code p0894
Hi,
im new to this forum so apologies if I’m posting in the wrong section. I recently was given a 2006 W211 e350 140,000 miles with 722.9 transmission currently in limp mode. I had MB replace the SBC and they suggested I service the transmission and quoted me $$$ to basically change the fluid and replace the filter.
I did did it myself and even inspected the solenoids in the valve body for debris. The fluid in the transmission was very old and smelled burnt but not scorched. The oil lacked viscosity but contained little debris and no obvious signs of clutch material. I inspected the outside of the filter but now wish i had cut opened the filter and looked inside for debris.
I put everything back together with new fluid and the car still will not shift past 2nd. Reverse is good and between 1st and 2nd is very smooth. I’m hoping to get some feedback on what the problem might me because I’ve heard 2-3 different causes each that require a substantial investment of money and time. The worst being changing the torque converter and transmission. The other 2 are there is a burnt clutch pack and the debris is on the inside of the filter or the valve body is bad.
Any help or suggestions is greatly appreciated. I don’t mind putting in the work myself and fairly competent with cars and have access to a lift, I’m just not interested in sinking a bunch of money into an old lady car. Not that my wishes have any impact on what repair is needed, I’m just throwing it out there for mercy from the Mercedes Gods for an easy fix.
Last edited by Mrg415; Mar 13, 2019 at 03:04 AM.
Reason: Spelling
Hi,
thanks for the reply. I had the same thought and that’s why I checked and cleaned the solenoids. Maybe should have replaced that one. The lack of clutch material is what makes me think it’s not something internal but that doesn’t mean that one or the clutch packs isn’t smoked. Btw I’m a lawyer as well so I’m sure there’s some joke to be made. “Two lawyers are working on a car...”
No real advice, but maybe get a code scanner like the Autel Diaglink that can scan MB specific codes and maybe you'll get some transmission specific codes that will help you better troubleshoot. About $95 on Amazon.
No real advice, but maybe get a code scanner like the Autel Diaglink that can scan MB specific codes and maybe you'll get some transmission specific codes that will help you better troubleshoot.
He already pulled a code (p0894), that's a "slipping" code.
Of course the sensors may not be able to distinguish between slippage due to worn clutch material and the clutch turning freely because it isn't applied...
Last edited by AUTOdidact; Mar 14, 2019 at 01:50 AM.
Thanks, that’s is a really good idea. I didn’t save a sample of the old fluid but is it reasonable to believe that the new fluid mixed with the fluid in the torque converter would be sufficient to test for contaminants? I have a Nag2 or I assume I do because that’s written on the conductor plate assuming it’s the original.
The attached is from an MB document that I was only able to crop this piece from. I have other information if you let me know your email.
thanks. As an afterthought I wished I would have checked the resistence on the solenoids or at least replaced the one controlling 3rd gear. I saw some videos with vague references to the ohms for each solenoid. Do you know the specific ohms and acceptable deviation? I just bought 8L of fluid for $60, thinking about pulling the pan back out and refilling fluid since I didn’t drain the fluid in the torque converter.
I got an AMG tech with his $22,000 Mercedes scan tool who is going to inspect it for me. He thinks the fluid is still dirty and the level is not set right. He ran it over with MB engineers and they all say it’s the fluid. But none of them have seen the car but they are confident. I brought up the possible solenoid issue and they say it won’t be that but I’m going to try it since I’m going to have the pan off.
I got an AMG tech with his $22,000 Mercedes scan tool who is going to inspect it for me. He thinks the fluid is still dirty and the level is not set right. He ran it over with MB engineers and they all say it’s the fluid. But none of them have seen the car but they are confident. I brought up the possible solenoid issue and they say it won’t be that but I’m going to try it since I’m going to have the pan off.
For MB workshops it's always the fluid because they can't / are not allowed to do anything else on the transmission
To my experience a fluid change may improve shift quality but never fixes a "real" issue. You should in any case also change the above mentioned shift solenoid, they are quite cheap.
Last edited by AUTOdidact; Mar 17, 2019 at 07:28 PM.
For MB workshops it's always the fluid because they can't / are not allowed to do anything else on the transmission
To my experience a fluid change may improve shift quality but never fixes a "real" issue. You should in any case also change the above mentioned shift solenoid, they are quite cheap.
my thoughts exactly. It seems ridiculous to throw away a transmission and torque converter because of a faulty solenoid or even bad valve, spring or contaminate in the valve body. They also recommend replacing the transmission if one of the clutch packs is burnt because the tolerances are too tight to replace. I don’t understand this because clutches over time lose tolerance and if the rollers Ned were that tight all of their transmissions would all fail. I’m not suggesting to machine my own clutches and the transmission reassembles without having to adjust anything. The pieces slide and lock into place. Maybe a few shims at the end so I’m your comment about not allowing their techs to service these transmissions makes sense. It’s like the bogeyman to them.
Its odd because the tech told me they use aftermarket oil filters when you pay them for their expensive oil change. Anyway, I ordered a new solenoid just in case it’s bad, might just put it in anyway as a physical malfunction would not show when I check the resistance. Is there a safe voltage I can apply to hear or see it open/close?
Any tips on checking/cleaning the valves without opening the valve body up? The oil was in really bad shape, any chance the valves are just dirty? 150,000 so there is still metal debris and maybe it plugged up the solenoid and/or valves?
Thanks for all the suggestions, I appreciate them.
Just curious if the drain and refill also included the fluid in the torque converter. The reason I ask is because these transmissions hold a good amount of fluid and it doesn't drain out very easily. Some manufacturers recommend doing 3 drain and refills to get enough fresh fluid in and the old fluid out.
I got an AMG tech with his $22,000 Mercedes scan tool who is going to inspect it for me. He thinks the fluid is still dirty and the level is not set right. He ran it over with MB engineers and they all say it’s the fluid. But none of them have seen the car but they are confident. I brought up the possible solenoid issue and they say it won’t be that but I’m going to try it since I’m going to have the pan off.
To be clear fault codes referenced must be stored together concerning valve body malfunction.
Just curious if the drain and refill also included the fluid in the torque converter. The reason I ask is because these transmissions hold a good amount of fluid and it doesn't drain out very easily. Some manufacturers recommend doing 3 drain and refills to get enough fresh fluid in and the old fluid out.
im new to this forum so apologies if I’m posting in the wrong section. I recently was given a 2006 W211 e350 140,000 miles with 722.9 transmission currently in limp mode. I had MB replace the SBC and they suggested I service the transmission and quoted me $$$ to basically change the fluid and replace the filter.
I did did it myself and even inspected the solenoids in the valve body for debris. The fluid in the transmission was very old and smelled burnt but not scorched. The oil lacked viscosity but contained little debris and no obvious signs of clutch material. I inspected the outside of the filter but now wish i had cut opened the filter and looked inside for debris.
I put everything back together with new fluid and the car still will not shift past 2nd. Reverse is good and between 1st and 2nd is very smooth. I’m hoping to get some feedback on what the problem might me because I’ve heard 2-3 different causes each that require a substantial investment of money and time. The worst being changing the torque converter and transmission. The other 2 are there is a burnt clutch pack and the debris is on the inside of the filter or the valve body is bad.
Any help or suggestions is greatly appreciated. I don’t mind putting in the work myself and fairly competent with cars and have access to a lift, I’m just not interested in sinking a bunch of money into an old lady car. Not that my wishes have any impact on what repair is needed, I’m just throwing it out there for mercy from the Mercedes Gods for an easy fix.
Hi, I know this is an old post but I’m having the same problem with my car. Can you please tell me what was your solution ?
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