2007 S65 with 53K miles, Transmission Slipping
Thread Starter
Junior Member
Joined: Jan 2003
Posts: 65
Likes: 2
From: Norcal Walnut Creek
SLK55, S65
2007 S65 with 53K miles, Transmission Slipping
Hello Gang,
I checked Xentry TCU event details - it had bunch of TCU Fault error, replace TCU and the fault codes are implausible gear.
The grear shift from 1 2 is rough and goes to N and throws a code. Once the car is past 4th gear it drives fine in 5th gear. However during down shift it goes to N instead of 4, 3.
I thought its due to cold transmission (in Bay Area (CA) it is considered cold at 55F). I tried warming up the car and the Transmission fluid temp is 80C. The same problem appears.
I read the TCU and simulated a TCU swap for SCN coding, the event log has no details but I still get transmission slippage implausible codes.
What are my options here?
1. Flush trans fluid?
2. Replace TCU?
3. Replace solenoid valve body with conductor plate?
2007 S65 AMG has 5 speed 722.6 Transmission. The TCU is on the passenger side foot well, hoping is an easy swap.
How difficult it is to swap the solenoid valve body?
I checked Xentry TCU event details - it had bunch of TCU Fault error, replace TCU and the fault codes are implausible gear.
The grear shift from 1 2 is rough and goes to N and throws a code. Once the car is past 4th gear it drives fine in 5th gear. However during down shift it goes to N instead of 4, 3.
I thought its due to cold transmission (in Bay Area (CA) it is considered cold at 55F). I tried warming up the car and the Transmission fluid temp is 80C. The same problem appears.
I read the TCU and simulated a TCU swap for SCN coding, the event log has no details but I still get transmission slippage implausible codes.
What are my options here?
1. Flush trans fluid?
2. Replace TCU?
3. Replace solenoid valve body with conductor plate?
2007 S65 AMG has 5 speed 722.6 Transmission. The TCU is on the passenger side foot well, hoping is an easy swap.
How difficult it is to swap the solenoid valve body?
MBWorld Fanatic!
Joined: Apr 2009
Posts: 1,264
Likes: 367
'06 MB S55 AMG; '04 Audi Allroad 4.2; '05 BMW M3 Conv.; '92 MB 500E
Also, did you check the old TCM to see if there was fluid in it? If there was, you will also need a transmission connector plug and seal. Known issue, where fluid wicks from the plug up into the TCM.
After that, fluid flush and filter. After that, conductor plate. After that, new transmission, though with 57k that’s unlikely.
My money is on fluid flush and filter.
maw
After that, fluid flush and filter. After that, conductor plate. After that, new transmission, though with 57k that’s unlikely.
My money is on fluid flush and filter.
maw
Thread Starter
Junior Member
Joined: Jan 2003
Posts: 65
Likes: 2
From: Norcal Walnut Creek
SLK55, S65
Thanks for the replies.
I got a new TCU which is in passenger side foot well. I replaced and tried to read adaptations from the old one and wrote to the new one. But the CEL came on. The car shifts into gear but I do not see display changing going from P to R to D to N etc. After power off and restart, the car does not shift at all but the display changes. Looks like I have to recode SCN and variant.
I put back the old TCU, at this point I dont think it is the TCU. I am assuming I have to flush the fluid, change filter and connector and see if the problem goes away. Will keep you guys posted.
I got a complete solenoid body with conductor plate from ebay as new but it wasnt,
722.6 TCU Transmission Valve Body Solenoid w/Conductor Plate for Mercedes-Benz | eBay
Returning this one and I might completely disassemble clean mine and put it back.
I got a new TCU which is in passenger side foot well. I replaced and tried to read adaptations from the old one and wrote to the new one. But the CEL came on. The car shifts into gear but I do not see display changing going from P to R to D to N etc. After power off and restart, the car does not shift at all but the display changes. Looks like I have to recode SCN and variant.
I put back the old TCU, at this point I dont think it is the TCU. I am assuming I have to flush the fluid, change filter and connector and see if the problem goes away. Will keep you guys posted.
I got a complete solenoid body with conductor plate from ebay as new but it wasnt,
722.6 TCU Transmission Valve Body Solenoid w/Conductor Plate for Mercedes-Benz | eBay
Returning this one and I might completely disassemble clean mine and put it back.
MBWorld Fanatic!
Joined: Apr 2009
Posts: 1,264
Likes: 367
'06 MB S55 AMG; '04 Audi Allroad 4.2; '05 BMW M3 Conv.; '92 MB 500E
Is there fluid in the old TCU? Answer that question “first”. If no, then there’s likely no connector O-ring leakage problem. Next, fluid and filter will likely solve the problem.
Doing anything else before doing those things is inviting trouble upon yourself. Please do not do it. Anything.
If and only if the fluid and filter do not resolve the problem, then proceed to the conductor plate but that should not be considered first time DIY work, IMO. If the solenoids read out OK then it’s doubtful you have a conductor plate problem anyway.
maw
Doing anything else before doing those things is inviting trouble upon yourself. Please do not do it. Anything.
If and only if the fluid and filter do not resolve the problem, then proceed to the conductor plate but that should not be considered first time DIY work, IMO. If the solenoids read out OK then it’s doubtful you have a conductor plate problem anyway.
maw
MBWorld Fanatic!
Joined: Feb 2012
Posts: 2,627
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From: Phoenix
222 S-65
Time to plug it in. Xentry will read what is missing.
Fresh fluid and a filter? Absolutely.
Would not be surprised to find it needs a conductor plate. Treat to do that requires programming.
Fresh fluid and a filter? Absolutely.
Would not be surprised to find it needs a conductor plate. Treat to do that requires programming.
MBWorld Fanatic!
Joined: Mar 2005
Posts: 1,033
Likes: 77
From: Wash. D.C.
'20 S63
Had a similar issue on my '08 CL65: https://mbworld.org/forums/s-class-w...nny-issue.html
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Thread Starter
Junior Member
Joined: Jan 2003
Posts: 65
Likes: 2
From: Norcal Walnut Creek
SLK55, S65
Ok I have good news. After changing the transmission fluid, it is no longer slipping. I drove to and from SF to Apple Valley this weekend, no issues after driving 900miles on the 5fwy.
The transmission fluid was thick as cake batter. The metal shavings are shiny and about 1 to 1.5mm wide but super thin. Its like panning for gold or steel in this case.
Come to think of it, the guy I purchased may have added some additives to transmission fluid. I noticed the cap red clip was broken. He was telling me what to add to fuel and oil every time I change it. I remember him mentioning "marvel mystery oil" and something else.
The transmission fluid was thick as cake batter. The metal shavings are shiny and about 1 to 1.5mm wide but super thin. Its like panning for gold or steel in this case.
Come to think of it, the guy I purchased may have added some additives to transmission fluid. I noticed the cap red clip was broken. He was telling me what to add to fuel and oil every time I change it. I remember him mentioning "marvel mystery oil" and something else.
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MBWorld Fanatic!
Joined: Apr 2009
Posts: 1,264
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'06 MB S55 AMG; '04 Audi Allroad 4.2; '05 BMW M3 Conv.; '92 MB 500E
Change it again after 1000 miles. Basically now. Make sure everything is flushed out. Maybe overkill, but probably not. But the most reputable Mercedes transmission rebuilders have told me very clearly (1) to do what I just suggested you do, after a rebuild; and (2) Mercedes transmissions do not like additives. The concern is compatibility with interior seals and orings. So whatever the previous guy put in there, you want it ALL out.
Cheers,
maw
Cheers,
maw
Last edited by maw1124; Feb 23, 2023 at 10:01 AM.
