Redcarrick
New Member
Help needed with ideas about a fault with auto transmission, sticking in gear.
I have a 2007 MB Viano CDi 2.2 with automatic transmission, and 140,000 genuine miles. I bought the vehicle as a non-runner following frontal crash damage, and I've now completed all of the repairs, which I have done myself. As part of the repairs I have replaced the radiator with transmission cooler (genuine new MB). I have serviced the transmission. I have replaced the transmission fluid, transmission filter, electrical connection and sump gasket. Everything was purchased from my local MB dealership. I have also purchased the MB transmission dipstick. Because the vehicle took frontal damage, unfortunately the Traction Control Unit (TCU) was damaged. I replaced this with a used one, same part number, same hardwear number and same software number. I have researched changing the transmission oil on Youtube, and followed the processes. I have filled the transmission oil to the +/- 25 degree as a approximate. I have still not achieved the +/- 80 degree temperature to get a definitive level, but I believe I am close. When I cleaned out the oil sump, there were no chunks or odd debris. The magnet had very fine material and what looked like general clutch wear material. After studying Youtube I was not alarmed by what I cleaned out of the oil sump.
My initial 2 weeks of use of the vehicle were flawless. Unfortunately, I am now getting regular problems. The transmission is smooth from start up, and then its a lottery as to when the fault happens. It could be 5 minutes, it could be 30 minutes. The transmission sticks in 2nd gear. It won't change up and it won't change down. It won't change if you use the manual shifter or automatic, it stays stuck. If you pull over, and select park and turn the engine off and give it 10 seconds. It comes back to life with no fault, then it's a lottery again when it will stick in 2nd gear again. When it happens, when you go from Drive to Park, it's a very violent shift, the vehicle makes a clunking noise. But once you restart it after 10 seconds its smooth again.
So my reasoning so far. I've changed the TCU, but I've been told because its like for like and its old (2007) that it won't need coding to my vehicle, so I think that's OK. I've serviced the transmission with genuine MB parts and oil, so I think that's OK. I'm just about there with the transmission oil level, still waiting to get to 80 degrees to make a definitive measure, could this be an issue? I've researched on the internet and the most common faults with the 722.6 transmission they seem to be the electric plug and the conductor plate. It sounds a pretty robust transmission fitted to many vehicles.
To progress from here. I've enquired with my local MD dealership and been quoted a hours diagnostic labour at £138 inclusive. I've also enquired with my local MB dealer about a new conductor plate, and been quoted £204 Inclusive. Only £64 difference between diagnostic and a new conductor plate, obviously having the diagnostic done and being told it's the conductor plate is the most expensive option at £342. I'd rather fix the problem by spending the least amount of money, that's the fun. I shall change the conductor plate myself, lots of good guidance on Youtube.
So, please, I'd be grateful for peoples two cents worth. Has anyone had the same problem? Does anyone have suggestions? Am I missing something obvious. Where should I go from here?
Thanks
I have a 2007 MB Viano CDi 2.2 with automatic transmission, and 140,000 genuine miles. I bought the vehicle as a non-runner following frontal crash damage, and I've now completed all of the repairs, which I have done myself. As part of the repairs I have replaced the radiator with transmission cooler (genuine new MB). I have serviced the transmission. I have replaced the transmission fluid, transmission filter, electrical connection and sump gasket. Everything was purchased from my local MB dealership. I have also purchased the MB transmission dipstick. Because the vehicle took frontal damage, unfortunately the Traction Control Unit (TCU) was damaged. I replaced this with a used one, same part number, same hardwear number and same software number. I have researched changing the transmission oil on Youtube, and followed the processes. I have filled the transmission oil to the +/- 25 degree as a approximate. I have still not achieved the +/- 80 degree temperature to get a definitive level, but I believe I am close. When I cleaned out the oil sump, there were no chunks or odd debris. The magnet had very fine material and what looked like general clutch wear material. After studying Youtube I was not alarmed by what I cleaned out of the oil sump.
My initial 2 weeks of use of the vehicle were flawless. Unfortunately, I am now getting regular problems. The transmission is smooth from start up, and then its a lottery as to when the fault happens. It could be 5 minutes, it could be 30 minutes. The transmission sticks in 2nd gear. It won't change up and it won't change down. It won't change if you use the manual shifter or automatic, it stays stuck. If you pull over, and select park and turn the engine off and give it 10 seconds. It comes back to life with no fault, then it's a lottery again when it will stick in 2nd gear again. When it happens, when you go from Drive to Park, it's a very violent shift, the vehicle makes a clunking noise. But once you restart it after 10 seconds its smooth again.
So my reasoning so far. I've changed the TCU, but I've been told because its like for like and its old (2007) that it won't need coding to my vehicle, so I think that's OK. I've serviced the transmission with genuine MB parts and oil, so I think that's OK. I'm just about there with the transmission oil level, still waiting to get to 80 degrees to make a definitive measure, could this be an issue? I've researched on the internet and the most common faults with the 722.6 transmission they seem to be the electric plug and the conductor plate. It sounds a pretty robust transmission fitted to many vehicles.
To progress from here. I've enquired with my local MD dealership and been quoted a hours diagnostic labour at £138 inclusive. I've also enquired with my local MB dealer about a new conductor plate, and been quoted £204 Inclusive. Only £64 difference between diagnostic and a new conductor plate, obviously having the diagnostic done and being told it's the conductor plate is the most expensive option at £342. I'd rather fix the problem by spending the least amount of money, that's the fun. I shall change the conductor plate myself, lots of good guidance on Youtube.
So, please, I'd be grateful for peoples two cents worth. Has anyone had the same problem? Does anyone have suggestions? Am I missing something obvious. Where should I go from here?
Thanks
