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I recently changed the conductor plate on my 02’ s55 amg. I didn’t change it personally, my long time friend a German specialist did the work. Before I changed it the car would go into limp mode and slip gears badly. After I changed it, the car was running as smooth as ever but now on cold mornings when I take the car out, it’ll shift rough and slip gears until I turn it off and start it again. Any ideas on what this could be ?
'06 MB S55 AMG; '04 Audi Allroad 4.2; '05 BMW M3 Conv.; '92 MB 500E
Did he (you) R&R the transmission fluid and filter at the same time? Has it been done before? Having zero information on your car (mileage, service history, etc.) those would be my first 2 checklist items. Also the trans plug and ORing. You need to make sure you don’t have transmission oil all through the electronics. Common issue.
Is the slip during a specific gear shift that always seems to be the problem? Or holding in a specific gear? Or in all gears?
I would start with verifying the fluid level is not too low or too high. The 2002 still has the dipstick tube for the transmission. You can check the fluid level when warm. Buy a MB ATF dipstick (I think for the 722.6 5-speed for that year) if it didn’t come with the car. You will have to pop off a little cap near the back of the engine, ignoring the warning that says something like “ATF. Do Not Remove!!”
My second bet would be a solenoid is not seated firmly from the conductor plate swap and your guy would have to do the job again. Making sure all the solenoids are seated and all valve body bolts are snugged.
Let us know how it goes. I have a conductor plate waiting in a box for my next ATF change.
'06 MB S55 AMG; '04 Audi Allroad 4.2; '05 BMW M3 Conv.; '92 MB 500E
My bet is on low fluid level when cold, warms up and expands, etc...
But question for @GrepAwk ... would you consider a conductor plate a maintenance item to be replaced as a matter of course... or wait until there are symptoms? I've always taken care of my trans fluid, filters and Plug so I've never had any problems... but as always with these cars, proactive might be better... just wondering your thoughts. Thanks,
I read a lot about the common problems in the first 5 years of my ownership and the AT conductor plate open circuits problem seemed to percolate to near the top for the 722.6.
So, when I made a decision to ignore MBUSA’s advice that ATF was supposed to be considered as “lifetime fill” and should change it (and coincidentally noticed the ATF leaking from the multi pin connector), I bought all the parts I thought I might need. (Plus lots of Titan ATF).
I wasn’t having any shifting problems. So I skipped swapping out the conductor plate. It’s in the box of “I might need that in 20 or 30 years” parts. Keeps company with the extra ABC accumulator, the front control arms, drive shaft flex disk, shaft support bearing....
'06 MB S55 AMG; '04 Audi Allroad 4.2; '05 BMW M3 Conv.; '92 MB 500E
Understood... boy don't I know about those spare parts secrets... most of mine are stored with "the mechanics"... the "Parts Are Gone" issues at MB is my main concern, having lived with the 500E... I already sourced a complete Chestnut Wood interior because all of those wood bits are now NLA... but I have the attached to show for it...
Back on point though, I've ignored MB on transmission and ABC fluid and filters as you know, so I'll put the conductor plate on the "if you see one grab it" list.
FWIW, what I've heard is the plug ORing develops a leak that goes unattended, some of the fluid drips out, some wicks up the harness, destroying first the conductor plate and then the TCU... started back on the 140 chassis cars, leading customers to abandon the cars at the dealerships... techs would rehabilitate the problem and have a 140 car for a song... so once you fix the plug you've likely fixed the issue permanently.
The electrical connector seal leak is very common. The first symptom is usually a few drops of ATF in your driveway every day.
As you mentioned, ATF can also wick up into the electrical cable and travel up above the floor, into the TCU and cause flakiness with the ICs inside.
The conductor plate normally lives immersed in the ATF. So it doesn’t get hurt by fluid. I think temperature fluctuations, pressure changes, and vibrations over time causes enough flexing in the plastic that it either cracks through an electrical trace, or one or more contact points for the solenoids terminals gets worn through or pulls away. (I’m guessing.)
'06 MB S55 AMG; '04 Audi Allroad 4.2; '05 BMW M3 Conv.; '92 MB 500E
@GrepAwk Thanks... the door trim was stock but rare... looked a long time to find it in an S55... the rear power door covers were stock and rare too, but exclusive to S600/65... and long NLA ... so tracking those down took a bit... benefit of parts hoarding.
Thanks for clarifying wicking vs. conductor plate... now I do recall that... memory getting bad between cars and problems.
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