ironforger

Hey guys,

I recently picked up this 2006 E320 Cdi 298k miles for my daughter. Car is in very good condition. Runs great. I got the service records, looking like it was fairly well maintained throughout life of the car.

Trans fluid flush was done around 100k miles and 200k miles. I'm pleased this was done and the current fluid still looks clean fresh and red. Not burnt or dirty.

Regardless I'm planning to do the trans fluid flush service and replace with Shell 134.

My question: I've read some about the connector plugs leaking, so I'm going to replace that when I service it. However, I've read alot about the conductor plates failing and wondering If I should just go ahead and replace the conductor plate while I have it apart proactively since it's never been done.

Daughter will be using this car for long distance highway trips. Thinking better safe than sorry & proactively fix.

Will I need to have the TCM reset after replacing the conductor plate? Or does this need to be done only if you have problems or error codes related to conductor plate? Car currently has no ecu codes.

Thanks!

kajtek1

Officially it is called "pilot bushing". We debate about the name and talking about "lost in translation" the best guess is that the EPC was translated from German by WIFE of the engineer
Answering the question, I replaced conductor plate on 5G over 10 years ago, when knowledge was low and DIY scanners did not exist.
That with bushing replacement did not resolve my intermittent limps and finally washing TCU did.
Over the time knowledge accumulate and IMHO 99% of conductor plates are replaced only becouse mechanic don't care about troubleshooting and have better markup on $300 plate, than on $10 bushing.
Good luck with your car. With SBC warranty MB USA gave it lately, they seem to be highly appreciated.

ironforger

Ok thanks for your reply but I'm so confused. What??? What does a pilot bushing have to do with automatic transmissions? Are we talking about the same thing? Also, you mentioned you replaced the conductor plate on 5G, what is 5G?

Just to clarify, I'm referring to the the "conductor plate" which sits on top of the valve body. Electrical connector connects directly to it. Here is an example of the part on fcpeuro: https://www.fcpeuro.com/products/mer...e-1402700861oe


Are we talking about the same thing?
Thanks!

konigstiger

06 e320 CDI has 5-speed transmission (722.6) kajtek1 is correctly suggesting to check 13 pin connection (pilot bushing) to conductor plate common for it to leak and ATF will follow harness up into transmission control unit. Given maintenance previously performed, ATF being fine, and no fault codes stored he is also correct rather than replacement inspect/clean solenoids, etc.

Having said this, I purchased each of my two daughters a home several years back, and in wanting peace of mind too, gutted/remodeled each in total as not to receive the 2AM panic call. For absolute peace of mind go ahead and replace conductor plate if this will make you sleep at night. May be overkill but I can relate with daughter “long distance highway trips” scenario.

See attachments. DIY depicts 210 but same procedure and although service campaign is not applicable to your vehicle it will give you better understanding of pilot bushing.

ironforger

Konigstiger, Thanks for clarifying and glad you can appreciate the overkill peace of mind factor. I must admit though I'm still confused about the "Pilot bushing" You mentioned: "kajtek1 is correctly suggesting to check 13 pin connection (pilot bushing) to conductor plate common for it to leak and ATF will follow harness up into transmission control unit." Here is an example of the "connector" as shown on fcp euro . Is this the actual item that you are also referring to as the "Pilot Bushing"? https://www.fcpeuro.com/products/mer...035400053#desc

Thanks!!

AUTOdidact

Yes, that's it. Your 2006 model should already be equipped with an oil barrier so the oil can't get up into the control unit any more, but still contact failures could occur due to oil contamination.

ironforger

Thanks! Phew! Good info. Thanks for clarifying! Not a big fan of confusion!

Where did they put the oil barrier on the 2006 model? Is it somewhere inline in the electric wire/cable? You also mentioned "but still contact failures could occur due to oil contamination.but still contact failures could occur due to oil contamination." Where are the contacts you are referring to?

Thanks!

AUTOdidact

Yes, the barrier is supposed to be inside the cable, and all the w211 models shall have it "already". 722.6 trans is on the market since 1996...

The plug connects from outside directly to the conductor plate, these contacts I ment. The connector (pilot bushing) only seals the plug to the oil inside the trans and hasn't contacts itself, only holes at the bottom to let the conductor plate's contacts get through.

If you pull the plug out and it's wet you know the connector doesn't seal properly.

ironforger

AUTOdidact: Great info. Thank you! I'll have a look at that connector (pilot bushing) when I do the service. I'll have a new one ready if needed.

AUTOdidact

Sorry, pilot bushing, not bearing, but this is a misleading term anyway...

ironforger

Yea you aint kidding man! I was all confused about that. Thanks everyone for clearing this up!! Pilot bushings are for manual tranmission input shafts! Whoever the hell decided to use that same name for an autotrans electric connector!?? Should be punished!!

kajtek1

Why would you punish the WIFE ?
10 replies to make 2 words clear to understand.

AUTOdidact

PS: Be aware the fluid isn't hot when doing this! Hot trans fluid expends a lot and the level could rise up where the connector sits.
Eventually jack the car up on the corner the plug is mounted (should be front right) to get the fluid level there as low as possible.

tjts1

Scan the transmission for stored codes before doing any work on it. Conductor plates do sometimes fail but it's rare. Does the transmission exhibit any odd behavior? There are other components in the valve body that sometimes wear out as well as solenoids.

kajtek1

Several times I replaced pilot bushing having car front on high ramps.
All I've got dripping was 1/2 cup of ATF, so most of the time did not even bother to add fluid after.

ptkacik

Ha! Yes, my pilot bushing started leaking and when the replacement part arrived, I thought "wait this isn't the correct part, it's just an electrical connector". Yes, that electrical connector is the problem and yes, it's called a pilot bushing (pilot bearing???).

It's good now,
Peter

AUTOdidact

The fluid shouldnīt drip at all, because if it does that, itīs also leaking into the conductor plateīs port (same height).
"Cold level" is even lower than the lower part of conductor plate while the plug rises up a little bit, so itīs the best to let the transmission cool down before replacing the "pilot bushing".
In case the fluid is drained also (which works better in a hot condition), this should be done before removing the bushing not to run into problems.

kajtek1

That could be true with European owners, where common sense tells to keep fluids level 1/2 between min and max scale.
In USA however, everything has to be topped off.

AUTOdidact

Min /max marks on the special dipstick used with the 722.6 trans are very close together - I cannot imagine provenance makes a big difference here

PS: The little plastic disc in the center of conductor plate rises with the oil level and closes a hole towards the (inner) casing of the trans to prevent oil leaking inside and foam up there (source: ATSG handbook), so oil level is intended to be lower at least in cold condition.