Transmission issue
Thread Starter
Member
Joined: Jul 2015
Posts: 118
Likes: 14
C63 Coupe
Transmission issue
Hello all,
I've looked through a bunch of posts and havent found a clear answer to this so I'm gonna give it a shot here
My car is a 2017 sitting at about 32k on the clock. At about 28k (probably 2-2.5 years ago) I did all major services including the transmission service at a reputable performance shop near me. The car has been great until the other day. As I was coming back from a drive (nothing stands out from that drive vs any other time) I was pulling away from a stop sign in comfort mode and the 2-3 shift seemed to slip and then bang into 3rd. Thought that was strange and switched modes.. its doing it in all modes including manual. Plugged in my scanner, no codes. Removed the tune and tried again same problem. Tried the tcu reset procedure, that didnt work. Disconnected the battery overnight, same thing. The transmission acts normally in every other gear its just the 2-3 upshift.
Praying its just low on transmission fluid. I have no leaks on my garage floor but who knows.
If anyone has experienced anything similar and knows what the issue is please let me know. I already purchased another transmission service kit from fcpeuro https://www.fcpeuro.com/products/mer...tosin-7229late
Thank you
edit- no tcu tune, just ecu
I've looked through a bunch of posts and havent found a clear answer to this so I'm gonna give it a shot here
My car is a 2017 sitting at about 32k on the clock. At about 28k (probably 2-2.5 years ago) I did all major services including the transmission service at a reputable performance shop near me. The car has been great until the other day. As I was coming back from a drive (nothing stands out from that drive vs any other time) I was pulling away from a stop sign in comfort mode and the 2-3 shift seemed to slip and then bang into 3rd. Thought that was strange and switched modes.. its doing it in all modes including manual. Plugged in my scanner, no codes. Removed the tune and tried again same problem. Tried the tcu reset procedure, that didnt work. Disconnected the battery overnight, same thing. The transmission acts normally in every other gear its just the 2-3 upshift.
Praying its just low on transmission fluid. I have no leaks on my garage floor but who knows.
If anyone has experienced anything similar and knows what the issue is please let me know. I already purchased another transmission service kit from fcpeuro https://www.fcpeuro.com/products/mer...tosin-7229late
Thank you
edit- no tcu tune, just ecu
Last edited by gforc3; Oct 22, 2024 at 08:12 PM.
MBWorld Fanatic!
Joined: Sep 2016
Posts: 1,723
Likes: 613
From: Australia
⏱️ 700HP Facelift converted C63 S Coupe with Drexler 3.06 plated LSD
Hello all,
I've looked through a bunch of posts and havent found a clear answer to this so I'm gonna give it a shot here
My car is a 2017 sitting at about 32k on the clock. At about 28k (probably 2-2.5 years ago) I did all major services including the transmission service at a reputable performance shop near me. The car has been great until the other day. As I was coming back from a drive (nothing stands out from that drive vs any other time) I was pulling away from a stop sign in comfort mode and the 2-3 shift seemed to slip and then bang into 3rd. Thought that was strange and switched modes.. its doing it in all modes including manual. Plugged in my scanner, no codes. Removed the tune and tried again same problem. Tried the tcu reset procedure, that didnt work. Disconnected the battery overnight, same thing. The transmission acts normally in every other gear its just the 2-3 upshift.
Praying its just low on transmission fluid. I have no leaks on my garage floor but who knows.
If anyone has experienced anything similar and knows what the issue is please let me know. I already purchased another transmission service kit from fcpeuro https://www.fcpeuro.com/products/mer...tosin-7229late
Thank you
edit- no tcu tune, just ecu
I've looked through a bunch of posts and havent found a clear answer to this so I'm gonna give it a shot here
My car is a 2017 sitting at about 32k on the clock. At about 28k (probably 2-2.5 years ago) I did all major services including the transmission service at a reputable performance shop near me. The car has been great until the other day. As I was coming back from a drive (nothing stands out from that drive vs any other time) I was pulling away from a stop sign in comfort mode and the 2-3 shift seemed to slip and then bang into 3rd. Thought that was strange and switched modes.. its doing it in all modes including manual. Plugged in my scanner, no codes. Removed the tune and tried again same problem. Tried the tcu reset procedure, that didnt work. Disconnected the battery overnight, same thing. The transmission acts normally in every other gear its just the 2-3 upshift.
Praying its just low on transmission fluid. I have no leaks on my garage floor but who knows.
If anyone has experienced anything similar and knows what the issue is please let me know. I already purchased another transmission service kit from fcpeuro https://www.fcpeuro.com/products/mer...tosin-7229late
Thank you
edit- no tcu tune, just ecu
MBWorld Fanatic!
Joined: Jun 2011
Posts: 2,119
Likes: 271
'13 GLK350 4matic,'10 C207,'15 GLA250,'07 Honda Odyssey, '18 GLE 43, '24 EQS 580
I have a rule on any car. If the fluid you taking out has a interval of every +50k kilometers, I let the dealer do it or do it myself. I would not trust anyone else aside the people who knows the correct procedure or myself who is trying to be a master mechanic. I would bring it to the dealer and let them redo the tranny sevice.
Thread Starter
Member
Joined: Jul 2015
Posts: 118
Likes: 14
C63 Coupe
Thank you for the replies. Someone else told me a dying battery could cause this also.. I have not replaced the battery since I bought the car so I’ll do that as well. When I plugged in my diagnostic tool I remember seeing the voltage at 12.3 which I didn’t think was low at the time but apparently it is.
I’ll be sure to update this thread after both the transmission service and battery replacement is done
I’ll be sure to update this thread after both the transmission service and battery replacement is done
Newbie
Joined: Oct 2024
Posts: 4
Likes: 0
Thank you for the replies. Someone else told me a dying battery could cause this also.. I have not replaced the battery since I bought the car so I’ll do that as well. When I plugged in my diagnostic tool I remember seeing the voltage at 12.3 which I didn’t think was low at the time but apparently it is.
I’ll be sure to update this thread after both the transmission service and battery replacement is done
I’ll be sure to update this thread after both the transmission service and battery replacement is done
Last edited by doggo; Oct 24, 2024 at 04:32 AM.
Trending Topics
MB World Stories
The Best of Mercedes & AMG
6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)
Verdad Gallardo
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
Member
Joined: Jun 2024
Posts: 191
Likes: 58
E320
Based on my experience with these transmissions, when you're getting a harsh 2-3 shift with no other symptoms, it's often related to the B2 brake band servo or the pressure control solenoid that manages the 2-3 shift. The metallic particles from normal wear can accumulate in the valve body channels, particularly around the 2-3 shift solenoid, causing erratic pressure control. I've also seen cases where the transmission conductor plate (the internal wiring harness) develops micro-cracks that only manifest during specific shift points, and the 2-3 shift is particularly vulnerable to this due to the load conditions during that transition. You'll want to do a complete scan of all modules, especially the TCM, with a proper scanner. I've been using my youcanic scanner lately because it gives me access to the live data streams during shifts, showing actual clutch application timing and pressure values - crucial for diagnosing Mercedes transmission issues. A basic scanner like the Launch Creader VII+ won't show you the adaptive shift parameters or solenoid response times that are essential for proper diagnosis. Sometimes these transmission issues store fault codes in the ESP module too, since the wheel speed sensors and transmission control are interconnected. Have you checked the transmission fluid level while the transmission is at operating temperature (80°C) with the engine running?
Thread Starter
Member
Joined: Jul 2015
Posts: 118
Likes: 14
C63 Coupe
Based on my experience with these transmissions, when you're getting a harsh 2-3 shift with no other symptoms, it's often related to the B2 brake band servo or the pressure control solenoid that manages the 2-3 shift. The metallic particles from normal wear can accumulate in the valve body channels, particularly around the 2-3 shift solenoid, causing erratic pressure control. I've also seen cases where the transmission conductor plate (the internal wiring harness) develops micro-cracks that only manifest during specific shift points, and the 2-3 shift is particularly vulnerable to this due to the load conditions during that transition. You'll want to do a complete scan of all modules, especially the TCM, with a proper scanner. I've been using my youcanic scanner lately because it gives me access to the live data streams during shifts, showing actual clutch application timing and pressure values - crucial for diagnosing Mercedes transmission issues. A basic scanner like the Launch Creader VII+ won't show you the adaptive shift parameters or solenoid response times that are essential for proper diagnosis. Sometimes these transmission issues store fault codes in the ESP module too, since the wheel speed sensors and transmission control are interconnected. Have you checked the transmission fluid level while the transmission is at operating temperature (80°C) with the engine running?
Thread Starter
Member
Joined: Jul 2015
Posts: 118
Likes: 14
C63 Coupe
No problem. I know the car is getting kind of old and that transmission is basically ancient tech at this point but this car as far as I've owned it has been cared for to the best of my ability. Service whenever required, not neglected in any way. Driven hard at times but thats what these cars are for. I'm just kind of shaking my head in disbelief that this is what the problem is. Based on some searching around this is an extremely common problem on all 722.x transmissions and the best part is the conductor plate is linked to your key so you cant just purchase a new one.
Hopefully this is the extent of the problem, I will update as this goes on
Also quick note just to help anyone in the future, I had not driven the car between the time it happened and the time I drove it to the shop. Driving to the shop the problem was way worse, in more gears, and also would not rev match downshifts at all in any mode (which it was ok with when it initially started happening). Stepping on the gas at highway speeds causing a downshift was violent
Hopefully this is the extent of the problem, I will update as this goes on
Also quick note just to help anyone in the future, I had not driven the car between the time it happened and the time I drove it to the shop. Driving to the shop the problem was way worse, in more gears, and also would not rev match downshifts at all in any mode (which it was ok with when it initially started happening). Stepping on the gas at highway speeds causing a downshift was violent
Last edited by gforc3; Oct 30, 2024 at 06:27 AM. Reason: edit
MBWorld God!
Joined: Dec 2019
Posts: 32,515
Likes: 6,350
No problem. I know the car is getting kind of old and that transmission is basically ancient tech at this point but this car as far as I've owned it has been cared for to the best of my ability. Service whenever required, not neglected in any way. Driven hard at times but thats what these cars are for. I'm just kind of shaking my head in disbelief that this is what the problem is. Based on some searching around this is an extremely common problem on all 722.x transmissions and the best part is the conductor plate is linked to your key so you cant just purchase a new one.
Hopefully this is the extent of the problem, I will update as this goes on
Also quick note just to help anyone in the future, I had not driven the car between the time it happened and the time I drove it to the shop. Driving to the shop the problem was way worse, in more gears, and also would not rev match downshifts at all in any mode (which it was ok with when it initially started happening). Stepping on the gas at highway speeds causing a downshift was violent
Hopefully this is the extent of the problem, I will update as this goes on
Also quick note just to help anyone in the future, I had not driven the car between the time it happened and the time I drove it to the shop. Driving to the shop the problem was way worse, in more gears, and also would not rev match downshifts at all in any mode (which it was ok with when it initially started happening). Stepping on the gas at highway speeds causing a downshift was violent
MBWorld Fanatic!
Joined: Aug 2007
Posts: 1,847
Likes: 799
From: Pacific Northwest
2001 S600 V12 Sold, 2011 Jaguar XFR Sold, 2017 S550 4-Matic, 2018 S63 AMG Sedan
No problem. I know the car is getting kind of old and that transmission is basically ancient tech at this point but this car as far as I've owned it has been cared for to the best of my ability. Service whenever required, not neglected in any way. Driven hard at times but thats what these cars are for. I'm just kind of shaking my head in disbelief that this is what the problem is. Based on some searching around this is an extremely common problem on all 722.x transmissions and the best part is the conductor plate is linked to your key so you cant just purchase a new one.
.........
.........
Thread Starter
Member
Joined: Jul 2015
Posts: 118
Likes: 14
C63 Coupe
Have you ever heard of this company??? They claim you don't need to code it, $325 for the repair seems great, if it works as advertised. https://circuitboardmedics.com/merce...BQbftBJW-axT3Z
Thread Starter
Member
Joined: Jul 2015
Posts: 118
Likes: 14
C63 Coupe
Update.. shop installed the new valve body/conductor plate and has not fixed the problem. They’re saying there’s a bigger problem with the transmission but haven’t gone into detail. They’re recommending replacing the transmission entirely with a used transmission with about 20k on it. I’m pretty conflicted about what to do. I would much rather replace whatever is broken on my transmission than swap to one that has probably been in a severe accident.
any insight would be greatly appreciated
thanks
any insight would be greatly appreciated
thanks
MBWorld God!
Joined: Dec 2019
Posts: 32,515
Likes: 6,350
Update.. shop installed the new valve body/conductor plate and has not fixed the problem. They’re saying there’s a bigger problem with the transmission but haven’t gone into detail. They’re recommending replacing the transmission entirely with a used transmission with about 20k on it. I’m pretty conflicted about what to do. I would much rather replace whatever is broken on my transmission than swap to one that has probably been in a severe accident.
any insight would be greatly appreciated
thanks
any insight would be greatly appreciated
thanks
