Hi all,

I have a 2011 E350 rear wheel drive with the 722.9 auto transmission with 153000 km's (95000 mi). It has had its transmission service as scheduled at the dealer a few years ago. Over the last few months I have had the following gear change issues gradually getting worse:

Rough shifting - Occurring regularly but not all the time - hot or cold. Up shift - 3 to 4, 4 to 5, 5 to 6. Down shift 5 to 4, 4 to 3, 4 to 2, 3 to 2. 3 to 2 has a very noticeable jerk while the other shifts seem to sometimes be delayed or slow
Automatically shifting to a lower gear and holding it on downhill runs under light / medium throttle - eg: it will drop from 6th to 4th at 60 km/h (38 mph) and wont up shift until a reasonable increase in throttle and then it jerks into the next gear.
Under heavy throttle will hang on to the gear and wont up shift until throttle is backed off and will sometimes hold onto the gear if throttle is backed off
Occasionally slow to engage drive or reverse

I have a iCarsoft2 MB and there are no codes showing on any of the modules.

Searching this forum leads me to suspect the valve body is the likely culprit. There is, of course, a possibility that something else may be the cause.

After talking with the Service Advisor, the dealer has quoted AU$3400 (US$2400) to replace the valve body with new part ex Germany and includes complete transmission service.

I estimate it would cost approximately AU$1500 (US$1000) for me to remove and clean the valve body & solenoids allowing for buying a couple of extra tools. I would class my mechanical skills as intermediate having just completed replacing the brake discs and pads. As it is my only household vehicle, if I get something wrong, I could end up with a AU$20000 (US$28500) paperweight blocking the driveway

Not having access to a hoist (car lift), would this "Weekend Wrench Warrior" be taking too big a risk by attempting to service the valve body with the car on a set of ramps?

 

I would say if you have a way to fill the transmission go for it. its not a bad job. all you do is remove the pan. remove the one time use bolts holding up the valve body i beilive there is about 10-12. disconnected the control unit and removed the valve body. then the rest is pretty straight forward. remove to solenoids and clean them

 

Let me give you my 2 cents. If you are not an experienced technician, I would definitely stay away from taking that VB apart. I rebuild this transmissions in house but when doing a full rebuild, we install a new/reman VB from the dealer. If we are just replacing the conductor plate or TCM then we do solenoid o-rings, new VB bolts, pan bolts, filter and pan gasket. Take a look at your coolant and see if it has transmission fluid in it. You will notice it looks milky. If there is transmission fluid in your coolant, then the clutches in your transmission are coming apart due to glycol contamination. This means the transmission cooler inside your radiator busted and is letting the 2 fluids mix.

 

I know that coolant in the trans fluid was an issue for the W211's but have you seen this on any W212's?
Also I have seen videos where they remove the VB and take out the solenoids and clean the screens. I am also been told that you can clean the solenoids as well and these remedies (assuming like you are saying the clutches aren't going) can improve the shift quality. This sounds DIY to me (not that I would necessarily have the guts to do it myself)

 

Hi all,

Thanks for the input. I checked the coolant yesterday and it is a nice crystal clear green.

The DIY video's I have seen only deal with cleaning the solenoid filters and don't completely disassemble the valve body. Threads I have read also indicate when you do completely disassemble the valve body casings, it is reasonably common to have alignment issues or warping of the plastic casings.So what I can achieve as an amateur may only be half the job just to save a bit of cash .

My experience with my previous car, a BMW 840, was you prepare for job A, find that part B needs doing but you have to remove part C, buy tool D and get stuck with trying to get part E off without attacking it with an angle grinder - "Mission Creep"
I think the biggest benefit for me of getting it done by MB is that if there is something else needing attention in the transmission, they are more likely than me to find it - plus if they need another part ex-Germany, I keep the loaner for 3 weeks . I will probably get the dealer to do it in late January as the part is 3 weeks ex Germany.

 

Another thought: Sometimes when you remove the valve body there are little things like check *****, screens, etc that fall out before you can see where they go. With so very little publically available information about Mercedes without paying for it, I would hesitate to know whether this is a possibility on your car before deciding to do this job yourself. I have removed several valve bodies on other makes and have had this happen to me, but they were Ford and Chevy, so it was easy to get the needed information.

 

@Money Pit , any update? I am facing similar issue with my tranny on 2014 Mercedes e250 and considering replacing the valve body but leaving the conductor plate and TCU from my original car. Did you replace the valve body and if so how is the car driving now?

 

Hi pnw-wa,

No I never did anything about it, I just accepted that for some driving styles (mine is light throttle, light breaking) the transmissions are just a bit jerky, particularly downshifting when coasting to a stop under light braking pressure. Another 50000 km (31000 miles) on the clock it is still pretty much the same - just an annoyance but I don't pay as much attention to it.

Although if you are going to do it, don't cut corners. Do it properly as half a job usually means doing it twice for three times the cost :-)

 

I have 0% doubt that a proper cleaning of the solenoid screens will make a massive improvement and add to the longevity of the transmission. I have often thought about doing this too.

In years past, I had an old 1995 Lexus LS400 that I cut my teeth on with car repair and maintenance DIY. I replaced all suspension components, mounts, even door seals and rear diff mounts. Flex discs, and so on. I was all over that car for a couple of years. Too mechanic at the local dealership actually bought it from in 2007, said it was the nicest one of that era he had ever seen before.

best thing I did was to remove the power steering solenoid from the rack and clean the screen. This was after I flushed the fluid and didn’t quite get the results I wanted from that process. So I did it again and included the solenoid screen procedure. It was night and day difference. Steered like a brand new car after that. Big cruiser with one finger steering.