Yet Another NAG1 Conductor plate experience

Diesel_Dog

2008 NCV3
Hello All, Long time lurker, first time poster. THanks to this site and youtube, I had no major issues today.

2 Days ago, I got a P0715 and she went into LHM... I actually got lucky, I was just 7 miles from my house at the tail end of 200 mile trip. I'm sure I could have cycled the ignition and cleared it, but I was off the hiway and so close to home on 20-30mph back roads, I just drove home in 2nd gear. Tranny has low miles but was used hard by PO. Has a slight whine sometimes between 30 and 40mph. I have owned this vehicle for one year/13k miles. I drive on the highway 90% of the time.

Dropped the pan and pulled the conductor plate/valve body today.

My takeaways...
Its just easier to remove the 3500 transmission support crosspiece... I figured this out after unbolting the trans tailpiece support bracket and trying to jack it high enough to get the pan/ filter out. I didnt want to tweak the engine mounts or stress anything else, so I resorted to option B... less than 5 minutes later I had the crosspiece out.

My conductor plate had NO PLASTIC SHIELDS/COVERS. As soon as I removed the valve body from the trans, I was staring at the solenoids.
EDIT: Some research has indicated that they are not present in some years/models and it seems not to be an issue.

The TCU connection plug/bushing were dry inside, no Trans fluid.

As I suspected there was a large amount of metal particles/sludge stuck to the speed sensor magnet. I wiped it off.

I removed each of the solenoids, cleaned the electric contact areas and inspected the screens, I ran a small magnet down close to the screens, didn't seem to pull much off them, they appeared clean.

I chose not to replace the conductor plate at this time because I do not want to deal with any ECU/TCU reprogramming issues right now.

I drained/caught 5.5 quarts of fluid..probably spilled maybe 4 - 6 oz.

All parts were stamped Mercedes Benz. If someone was into this tranny before me, and if they replaced parts, they were OE.

I was able to clear the Pending P0715 using my Torque Pro app.

I will reassemble on friday morn, will update this post. Sorry, no pics, but y'all know what a conductor plate looks like.
 
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Diesel_Dog

2008 NCV3
Part 2

In my quest for cleanliness I sprayed the Valve body and conductor plate with a bit of Electrical Contact cleaner. It certainly removed some more microscopic (metal?) pieces. It says its is safe on plastic and soft metals.

I torqued the solenoids back down, reinstalled the valve body/conductor plate into the transmission. Torqued all the bolts with my new 1/4" torque wrench (it is so tiny, it makes me feel like a giant), installed the new filter and gasket and put the pan on. Installed the new pilot bushing/barrel plug receiver. and put the plug in.

Reinstalled the Crossmember and reconnected the exhaust hanger.

I had wrapped the trans in a garbage bag, and there was another 6 oz of fluid that it caught, bringing me up to 5.7 qts caught and an unknown quantity spilled.
I put in 6 quarts of Valvoline Maxlife. Started it, put it in gear and checked it using the COLD area on the dipstick, it was a low, so I added another half quart...

Took her for a 30 minute rip... Ran great, shifted well, no codes thrown, no leaks.

Checked the fluid level again, now on the HOT scale... Slightly overfilled... Dang... Guess I will drain out 4-6 oz.

Total Cost.
9 hrs labor- (yes I went very slow and double, triple checked my work) - FREE
Barbie sized torque wrench - $45
2 jugs of Valvoline maxlife - $39
Filter and Gasket - $15
Pilot Bushing (Thats what the dealer calls it) - $16
Total $115 (Actually $70 if you dont count the tool)

I did a 11,600 mile roadtrip last year with almost no issues, I hope to have another great experience this year.

THanks for reading, hope it helps someone.
 

Diesel_Dog

2008 NCV3
Well, after 50 miles, the P0715 came back. Annoying but not entirely unexpected. Hope I can do this process again with the arm that I injured while patting myself on the back.


Before I repeated the process I Just wanted to check everything I could... so I removed the driver seat and accessed the TCU to have at it with my multimeter.

First pic show System voltage, pin 38 (12+VDC)

IMG_20200929_155139.jpg

Second pic shows TCU voltage pin 13 (4-8VDC)

IMG_20200929_155121.jpg

Third pic shows Solenoid pin 36 and pin 37 (~5 ohms)

IMG_20200929_155011.jpg


Everything checked out ok. So I removed the old conductor plate and took it over to the Stealer, for the core charge swap. Got my new (reman) plate and installed it. Only took 4 hours this time. Put fluid in it and I am about to take it for a test drive.
 

Diesel_Dog

2008 NCV3
1.5 hour test drive, so far so good. Got the fluid level perfect this time.

More takeaways.

I cleared the fault in the ECU/TCM before removing the existing conductor plate. After installing the new one, I did not get any new codes.

Just to cover your bases, you may as well check your TCU like I did, you dont even have to remove the seat, you can remove the fuse panel under the seat, and unclip the TCU and pop it out the fuse panel hole. (Also you are checking for fluid contamination)

When refilling, Add Trans fluid 6 oz at a time and re check the level. (My final top off was 2oz to get it perfect)

Inspect the plug and wiring, it is right next to the exhaust/DOC. The corrugated plastic wire shield had melted away in one spot. There was no heat shield on the plug like I have seen on some videos.

Watch videos, and read posts, I watched at least 15 vids and read for hours on this site and elsewhere. Dont turn a $400 job into a $5000 job.

Thanks for reading.
 
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Cliffcashcomedy

New member
Part 2

In my quest for cleanliness I sprayed the Valve body and conductor plate with a bit of Electrical Contact cleaner. It certainly removed some more microscopic (metal?) pieces. It says its is safe on plastic and soft metals.

I torqued the solenoids back down, reinstalled the valve body/conductor plate into the transmission. Torqued all the bolts with my new 1/4" torque wrench (it is so tiny, it makes me feel like a giant), installed the new filter and gasket and put the pan on. Installed the new pilot bushing/barrel plug receiver. and put the plug in.

Reinstalled the Crossmember and reconnected the exhaust hanger.

I had wrapped the trans in a garbage bag, and there was another 6 oz of fluid that it caught, bringing me up to 5.7 qts caught and an unknown quantity spilled.
I put in 6 quarts of Valvoline Maxlife. Started it, put it in gear and checked it using the COLD area on the dipstick, it was a low, so I added another half quart...

Took her for a 30 minute rip... Ran great, shifted well, no codes thrown, no leaks.

Checked the fluid level again, now on the HOT scale... Slightly overfilled... Dang... Guess I will drain out 4-6 oz.

Total Cost.
9 hrs labor- (yes I went very slow and double, triple checked my work) - FREE
Barbie sized torque wrench - $45
2 jugs of Valvoline maxlife - $39
Filter and Gasket - $15
Pilot Bushing (Thats what the dealer calls it) - $16
Total $115 (Actually $70 if you dont count the tool)

I did a 11,600 mile roadtrip last year with almost no issues, I hope to have another great experience this year.

THanks for reading, hope it helps someone.
Hello! So I just did basically the same service you’re saying. I do not think I overfilled, I used the same fluid, I replaced the little barrel plug I was leaking fluid there. Now my van is in LHM. Do you think it’s because of the new plug?
 

Diesel_Dog

2008 NCV3
Hi, I am no expert, I am always happy to theorize...
A pin could have been bent or pushed out of place when you were installing the new pilot bushing/plug receiver, or perhaps enough fluid was pushed into the TCM to cause a fault...? Remove the plug, spray it out with electrical cleaner, stick your phone up in front of the bushing and take a picture of the pins... there should be 13 I think. Check the TCM for trans fluid intrusion.

If you do your own service, a code reader, multimeter and a trans dipstick are not optional tools, these beasts are way too complicated and expensive to be guessing.
 

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