722.9 transmission: Valve body or conductor plate issue?
Thread Starter
Newbie
Joined: Nov 2024
Posts: 7
Likes: 3
2015 E350 (W212)
722.9 transmission: Valve body or conductor plate issue?
2015 E350 here with the 722.9 transmission, over 100k miles. Transmission fluid changed around 80k by dealer just before I bought it. Had a harsh 2-3 upshift at low speed, and a harsh 5-4 acceleration downshift. All other shifts very smooth under all conditions.
The 2-3 issue completely disappeared when I reset adaptation values myself, but no improvement to the 5-4. It downshifts from 5 to 4 smoothly under deceleration and even under light acceleration, but the kickdown delivers a startling kick in the pants under medium to heavy acceleration, unlike any other gear. Definitely not how it left the factory.
No codes are thrown at all by the transmission module.
From what I've read, these problems tend to be either a faulty speed sensor on the conductor plate, or a component (solenoid, clutch, brake?) in the valve body. I'm handy but I don't really understand transmissions at that level.
Anyone with more experience have a suggestion for most likely cause, further testing I should do, or anything else helpful? I don't want to attempt to replace/repair something that isn't faulty.
The 2-3 issue completely disappeared when I reset adaptation values myself, but no improvement to the 5-4. It downshifts from 5 to 4 smoothly under deceleration and even under light acceleration, but the kickdown delivers a startling kick in the pants under medium to heavy acceleration, unlike any other gear. Definitely not how it left the factory.
No codes are thrown at all by the transmission module.
From what I've read, these problems tend to be either a faulty speed sensor on the conductor plate, or a component (solenoid, clutch, brake?) in the valve body. I'm handy but I don't really understand transmissions at that level.
Anyone with more experience have a suggestion for most likely cause, further testing I should do, or anything else helpful? I don't want to attempt to replace/repair something that isn't faulty.
Out Of Control!!
Joined: Apr 2019
Posts: 11,921
Likes: 6,770
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
2015 E350 here with the 722.9 transmission, over 100k miles. Transmission fluid changed around 80k by dealer just before I bought it. Had a harsh 2-3 upshift at low speed, and a harsh 5-4 acceleration downshift. All other shifts very smooth under all conditions.
The 2-3 issue completely disappeared when I reset adaptation values myself, but no improvement to the 5-4. It downshifts from 5 to 4 smoothly under deceleration and even under light acceleration, but the kickdown delivers a startling kick in the pants under medium to heavy acceleration, unlike any other gear. Definitely not how it left the factory.
No codes are thrown at all by the transmission module.
From what I've read, these problems tend to be either a faulty speed sensor on the conductor plate, or a component (solenoid, clutch, brake?) in the valve body. I'm handy but I don't really understand transmissions at that level.
Anyone with more experience have a suggestion for most likely cause, further testing I should do, or anything else helpful? I don't want to attempt to replace/repair something that isn't faulty.
The 2-3 issue completely disappeared when I reset adaptation values myself, but no improvement to the 5-4. It downshifts from 5 to 4 smoothly under deceleration and even under light acceleration, but the kickdown delivers a startling kick in the pants under medium to heavy acceleration, unlike any other gear. Definitely not how it left the factory.
No codes are thrown at all by the transmission module.
From what I've read, these problems tend to be either a faulty speed sensor on the conductor plate, or a component (solenoid, clutch, brake?) in the valve body. I'm handy but I don't really understand transmissions at that level.
Anyone with more experience have a suggestion for most likely cause, further testing I should do, or anything else helpful? I don't want to attempt to replace/repair something that isn't faulty.
You have ok ATF already...
Double check how many non-TCU chassis faults are reported.
Poor engine throttle control are likely causing you delayed bangy shifts. Nothing else too fancy.
Last edited by CaliBenzDriver; Jul 22, 2025 at 07:48 PM.
Member
Joined: May 2018
Posts: 214
Likes: 66
From: SoCal
2020 E450 4matic wagon
What is the history on your transmission and engine mounts?
I believe that your transmission mount is vulcanized rubber.
Replaced mine and it's such a noticeable smoother gear shift sequence.
I believe that your transmission mount is vulcanized rubber.
Replaced mine and it's such a noticeable smoother gear shift sequence.
Last edited by mercerized; Jul 23, 2025 at 01:23 PM.
Newbie
Joined: Jul 2025
Posts: 10
Likes: 0
2009 Mercedes C63
722.9 transmission
I have a 2009 C63 and I blew my original trans and my mechanic got a used one(transmission conductor plate and valve body) and told me it’s from a c63. So we installed it and it was fine for about a month then I started getting problems with the conductor plates we decided to send out the conductor plate to UpFix a local company who rebuilds them and when they looked at the part number on the conductor plate it came up as a 2010 r350…. Can anyone help out with this I’m starting to wonder maybe he put a r350 transmission insta my c63.
Senior Member
Joined: Nov 2007
Posts: 419
Likes: 16
From: NY
2014 E550; 2003 E500
What do you mean by Engine Throttle control failing? The actual throttle body itself, the pedal, or something else? I’ve always thought something like this was the cause as the engine and transmission seems to be not communicating well on shifts.
Out Of Control!!
Joined: Apr 2019
Posts: 11,921
Likes: 6,770
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
SIMPLE STOCK IMPROVEMENTS
This is a combination of issues from
the ECU working the throttle body
plus the busy CAN-Bus:C.
> HOW IS THAT ...
-1- the ECU does not have perfect throttle control for at least two reasons: the air intake camshaft is made unstable by low oil pump pressure and the chassis variable voltage (12.6 to 14.9) is not well tolerated by TB coils (regardless of pulsed width).
That boils down to stock TB response can be improved.
-2- The CAN-C is shared between ESP- ECU-TCU-ISM-FSPU... is swamped to max bandwidth, it delivers delayed data. This prevents timely cooperation and disables matched rpm using engine throttle.
The long story short is the platform needs effective stability:
- stable OIL pressure to position VVT
- stable VOLTAGE to drive all electric coils
- stable CAN-Buses from CGW
- stable sealed compressions
- stable HEAT levels (coolant/oil/ATF)
- equal predictable powertrain maps.
> You can begin experimenting with a really simple REBOOT + Float: effective for a while (from 1 day, to 1 week).
Every stock condition you improve comes closer to nimble "pressure sensitive" throttle with seemless shifts. Focus on the engine, the great tranny will match.
Last edited by CaliBenzDriver; Aug 2, 2025 at 02:41 PM.
Newbie
Joined: Nov 2021
Posts: 10
Likes: 1
Mercedes E350
2015 E350 here with the 722.9 transmission, over 100k miles. Transmission fluid changed around 80k by dealer just before I bought it. Had a harsh 2-3 upshift at low speed, and a harsh 5-4 acceleration downshift. All other shifts very smooth under all conditions.
The 2-3 issue completely disappeared when I reset adaptation values myself, but no improvement to the 5-4. It downshifts from 5 to 4 smoothly under deceleration and even under light acceleration, but the kickdown delivers a startling kick in the pants under medium to heavy acceleration, unlike any other gear. Definitely not how it left the factory.
No codes are thrown at all by the transmission module.
From what I've read, these problems tend to be either a faulty speed sensor on the conductor plate, or a component (solenoid, clutch, brake?) in the valve body. I'm handy but I don't really understand transmissions at that level.
Anyone with more experience have a suggestion for most likely cause, further testing I should do, or anything else helpful? I don't want to attempt to replace/repair something that isn't faulty.
The 2-3 issue completely disappeared when I reset adaptation values myself, but no improvement to the 5-4. It downshifts from 5 to 4 smoothly under deceleration and even under light acceleration, but the kickdown delivers a startling kick in the pants under medium to heavy acceleration, unlike any other gear. Definitely not how it left the factory.
No codes are thrown at all by the transmission module.
From what I've read, these problems tend to be either a faulty speed sensor on the conductor plate, or a component (solenoid, clutch, brake?) in the valve body. I'm handy but I don't really understand transmissions at that level.
Anyone with more experience have a suggestion for most likely cause, further testing I should do, or anything else helpful? I don't want to attempt to replace/repair something that isn't faulty.
Poor shifts are a matured issue developed with multiple layers. They are not caused by the TCU that always delivers the very best possible shifts including sloppy "best efforts". Great shifts are really seemless, bad one are delayed out bangy.
This is a combination of issues from
the ECU working the throttle body
plus the busy CAN-Bus:C.
> HOW IS THAT ...
-1- the ECU does not have perfect throttle control for at least two reasons: the air intake camshaft is made unstable by low oil pump pressure and the chassis variable voltage (12.6 to 14.9) is not well tolerated by TB coils (regardless of pulsed width).
That boils down to stock TB response can be improved.
-2- The CAN-C is shared between ESP- ECU-TCU-ISM-FSPU... is swamped to max bandwidth, it delivers delayed data. This prevents timely cooperation and disables matched rpm using engine throttle.
The long story short is the platform needs effective stability:
> You can begin experimenting with a really simple REBOOT + Float: effective for a while (from 1 day, to 1 week).
Every stock condition you improve comes closer to nimble "pressure sensitive" throttle with seemless shifts. Focus on the engine, the great tranny will match.
This is a combination of issues from
the ECU working the throttle body
plus the busy CAN-Bus:C.
> HOW IS THAT ...
-1- the ECU does not have perfect throttle control for at least two reasons: the air intake camshaft is made unstable by low oil pump pressure and the chassis variable voltage (12.6 to 14.9) is not well tolerated by TB coils (regardless of pulsed width).
That boils down to stock TB response can be improved.
-2- The CAN-C is shared between ESP- ECU-TCU-ISM-FSPU... is swamped to max bandwidth, it delivers delayed data. This prevents timely cooperation and disables matched rpm using engine throttle.
The long story short is the platform needs effective stability:
- stable OIL pressure to position VVT
- stable VOLTAGE to drive all electric coils
- stable CAN-Buses from CGW
- stable sealed compressions
- stable HEAT levels (coolant/oil/ATF)
- equal predictable powertrain maps.
> You can begin experimenting with a really simple REBOOT + Float: effective for a while (from 1 day, to 1 week).
Every stock condition you improve comes closer to nimble "pressure sensitive" throttle with seemless shifts. Focus on the engine, the great tranny will match.
Can you please elaborate on what you mean by Reboot + Float. Thank you. Are you referring that there might be an underlying engine issue that is causing this transmission symptom ?
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Out Of Control!!
Joined: Apr 2019
Posts: 11,921
Likes: 6,770
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
TAMING WILD TRANNY
I have the exact same issue - exact same gear 5>4 under acceleration and 2>3 when shifts at high RPM. Please keep me updated if you end up finding the cause of the problem and I will do the same.
Thank you for the explanation.
Can you please elaborate on what you mean by Reboot + Float. Thank you.
Are you referring that there might be an underlying engine issue that is causing this transmission symptom ?
Thank you for the explanation.
Can you please elaborate on what you mean by Reboot + Float. Thank you.
Are you referring that there might be an underlying engine issue that is causing this transmission symptom ?
-- SPEED: High gears selected at low speed such as 6th gear at 35mph!
-- HOW: Sloppy-slipery shifts instead of matched RPM's
-- WHEN: Delayed banging-shifts instead of coordinated shifts
Should you recognize these conditions, you can have a look here to experiment turning this around simply.
Once the engine gets predictable, tranny begins to match it perfectly with its self-adaptations.
Great seemless shifts are instantaneous & fast with matched shaft RPM in the gear that delivers normally driveable output torque: 1,2 or 3 not 5 or 6.
Last edited by CaliBenzDriver; Aug 4, 2025 at 09:51 PM.
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