722.9 Auto box problem. No drive at all. Any help appreciated.

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Brian220CDI

Member
Joined
Sep 23, 2020
Messages
58
Location
Wrexham, North Wales
Car
C Class 220CDI S204 2011
Hi Guys, I know this has probably been discussed several times but I'm getting confused with everyone's opinions on the problems they have had. I haven't got any experience with Auto boxes except taking engines off them.

I drive a C220 2011 with the 7 speed Auto with stop start but yesterday at 75mph on the motorway overtaking all drive went. I didn't have any notice, no noises, no bangs etc it just went. I managed to get over and to the bottom of the slip road so got away with it. No warning lights either.

I was sitting waiting to be recovered and plugged a Carly adapter in while waiting. Codes that came up are as follows

P0894- the gear is implausible or the transmission is slipping.
P076F- The gear is implausible or the transmission is slipping (Gear 7).
P0734- The gear is implausible or the transmission is slipping (gear 4).
All pointing firstly to oil level as easiest and cheapest fix.

I had the engine out about two weeks ago to sort out an oil leak on the engine that had bugged me in 8 months of ownership and sorted that out but yesterday was a 60 mile round trip with a few stops on the way before it went. I left the gearbox in place when i removed the engine and didn't touch it until the engine was back in and then topped up the gearbox oil level after it had been running for about an hour and 20 mins while sorting out coolant and oil levels etc. The gearbox filter was changed at Christmas with new fluid from Mercedes spec 236.15 (Blue), green level pipe, new seal and bolts. All I needed to do was just top it up as lost some oil from the torque converter when the engine was pulled.

Today I have been to Mercedes and bought another 5 litres of 236.15 (£53) and ran the car for half an hour to 40 mins and checked again. It seamed ok but I put another litre in just to make sure as it can easily be dropped again. I cleared all the codes off the Carly adapter and all looked good. Selected D and its just like being in neutral same with R too. Nothing has changed from yesterday when I was recovered.

It seams strange that there are no codes anymore? Surely if there was a fault still it would push out a code? I've left the car now as its at my mother-in-laws as she has a flat drive to do the work and going to go back later to see if a cool down and being locked for a while sorts it out but not holding my breath.
 
Probably wont make any difference to your problem, but did you measure the fluid with the car level and at 45 degrees ?
 
Probably wont make any difference to your problem, but did you measure the fluid with the car level and at 45 degrees ?
Hi geoffus, the car was level and was running for about 40 mins before I dropped the sump plug. It normally takes around half an hour to get up to 45 degrees but I don't have Star to read the oil temp. It was warm to touch so was above my body temp :rolleyes: (getting technical here) although was about 5 degrees outside.
 
Have you unplugged it and plugged it back in again ? the ECU plug on the side of the gearbox I mean. Kind of clutching at straws, but its an easy thing to try.
That could be worth a try although it seams strange that there are no codes now. If a connection was caught by a stone or something but I don't have my under body trays back on yet as still testing to make sure oil leak is resolved there would be a code saying to ground or intermittent but thanks anything is worth looking at as I cant get in touch with any garages till Monday.
 
Well not often with the 722.9 box you get no drive at all,more often it goes in limp mode in 2nd,but it can happen and it is down to the electro plate valve body failing big time,your fault codes are saying the box cannot select the right gear and so it selects nothing ,you are handy with a spanner and there are a few videos on utube,of how to remove the electroplate,you would need to send it to a repairer,I do not know of anybody in Wales but look up valvebodiesuk they have a good rep for sorting it out
 
Well the good news is it is a 2011 motor so the bit about early boxes does not come into play,but as Petrol Pete said a engine out job is far harder than removing the elctro plate and once it is repaired you can just put it back in and it does not need coding like a new electro plate.
 
Yes thanks Zipdip and Petrol Pete. I was looking into this and found a company in Derbyshire that repair them but just don't know if its this. They charge £225 plus Vat for repair and 2 to 3 day turn around. Could be back for next weekend!


I've emailed them but they don't open until Monday. Wont take long to drop gearbox oil and sump off to get to it and correct it is easier than the engine :)

This is the way I'm leaning but would love someone to come on here and say yes I had this last week and it was this! :wallbash::wallbash::wallbash::wallbash: whats the chances?
 
What about getting an icarsoft reader , that may be able to help pinpoint any probs for the £100-150 cost it would take ?
 
Well you have the codes,but if in doubt get a mobile mechanic with a star to read them,I have found in the past that these boxes do not always give you codes,the ones you have posted are all pointing to the box not knowing what the speed is and so it is not selecting anything so no drive,but I can see your point,but as repairs go on a mercedes £200 odd quid is not a lot,but it is your decision.
 
Petrol Pete this is the same company that I linked above but on eBay. Listed a little cheaper so might click on that one If that's the way I decide to go.
 
What about getting an icarsoft reader , that may be able to help pinpoint any probs for the £100-150 cost it would take ?
The problem I've got with the cost of this is the cost of everything else. Just spent a fortune on doing the engine seals etc and a new starter motor and battery all within the last 3 weeks. I'm not having much luck with this car and the costs are just building up. My misses is understanding but eventually she will tell me to sell the car like I did with her BMW 1 series last year that needed a new engine and I don't want that. :) :rolleyes:
 
Bottom line is Brian is that you will have a hard time selling it for sensible money as it is now. I understand how peed off you might be with this car but getting the transmission fixed is pretty much a 'must do' . :(
 
And 2 hours later the TCU is off. 😆 I'm going to book it in tonight on ebay and send it next day tomorrow in my local post office so I have a fighting chance to get it back ready for next weekend I hope. Start with that as it seams to be the reason on all the forums I'm looking at. P.s the wife has authorised the money 😆🤣😂
 
And 2 hours later the TCU is off. 😆 I'm going to book it in tonight on ebay and send it next day tomorrow in my local post office so I have a fighting chance to get it back ready for next weekend I hope. Start with that as it seams to be the reason on all the forums I'm looking at. P.s the wife has authorised the money 😆🤣😂
Keep us informed how you get on.
 

Just placed this order for £195 with Essex recon on Ebay with the same quick turn around. Saved £20 so spent £30 on new bolts and gasket for the sump 😅😅😂🤣🤣

Was an easy but messy job and not great for the size of me getting under the car on axle stands but its out ready for strip down tomorrow morning.

I will let you all know how I get on. Thanks for the help and support.
 

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I strongly suspect you have sheared the drive lugs in the pump where they fit into the torque converter. I have seen this before a few times. Oil leaking from the torque converter when you pulled the engine means you lifted the converter past its seals. It will have pulled off the drive dogs. It will go back with the dogs misaligned, but it will fail shortly after, usually within 50 miles. If you look at live data in the gearbox and check the oil pressure you will probably find it at zero. This confirms the pump isn't running.
 

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