Nag1 TECH ALERT

kite

Member
I have some somewhat annoying transmission behavior on my 2004 van, though I'm not sure how abnormal it actually is. Curious to hear from others if they notice this, and if the speed sensor cleaning (or other maintenance) may improve it.

behavior 1.
During normal acceleration from a stop, upshifts have the feeling of slipping (especially to 2nd and 3rd gears). Let's say the shift starts from 2300rpm, RPMs will drop to around 2000rpm, and stay there while speed increases, then rise again once engine speed and transmission speed match. If I step harder on the accelerator during this "not fully engaged time," engine speed drops below 2000 quite quickly, fully engaging the higher gear.
My first thought (or hope) is that this is the torque converter clutch engaging, and is working as intended. But these transmissions remain a bit of a mystery to me.

behavior 2
When coasting, RPMs drop some expected. When I press on the accelerator, RPMs overshoot, then settle into gear. This gives the feeling of delayed response, and also just makes me worried my transmission has issues.
For instance, I can be coasting at 22mph @ 1200 rpm. When I press the accelerator, RPMs briefly reach 18-1900, then drop into gear at 1500rpm.
Here's a video that hopefully shows it: https://photos.app.goo.gl/w1fAIUC6Y63aJLnP2

Thanks for any insight you might have!
 

SprinterSnale

'05 T1N 3500 - NorCalSprinterCampout
My turn with a naughty NAG1. 05 T1N 3500 183K
I've had sporadic soft limps for awhile sticking in 3 or 4 progressing in frequency. I cleaned grounds contacts and strap, checked light bulbs, relay and TCU looks clean. After clearing codes, the 'Speed Senor 3' malfunction reappears. Dr.A has been in touch and said check wiring to sensors first. I will measure resistance, can't scope it. The wiring 'looks' good (not fried by exhaust).

I have one wicking question that I can't find addressed in this thread.
--Does wicking occur on the outside of the wires (on insulation exterior) or is it possible the capillary action occurs inside the insulation along the copper strands? --

The reason I ask is there is a section of wire loom just before turning upward toward the driver seat that appeared to be oily...but nowhere else along the loom run. I imagine it could have been oil from the road or slop from above at some point. But not sure.

The tranny and TC fluid, filter and replacement connector service was performed 30k back, but I'm going to use new fluid and insert a new conductor plate to hopefully disappear from this thread.

I talked with my local ambulance fleet mechanic who said he has done a few conductor plate refits, but hasn't had to perform this on any NCV3's newer than 2010. He didn't want to do mine, but instilled confidence I could do it ("Yeah, I host a Sprinter Campout" haha).

Take a look on YouTube, and it is obvious this is a persistent problem on many '00 era 5-speed Mercedes transmissions that many have successfully solved, often with Chinese conductor plates (no thank you).
My booty from EPSD just over $300 to the door...


Time to sterilize the work bench and check the weather. Don't want to do it on a windy day.
 

Aqua Puttana

Poly - Thread Finder
... or is it possible the capillary action occurs inside the insulation along the copper strands? ...
In my mind that is exactly how it happens. The insulating sleeve is a sealed tubing with the ATF wicking along the copper strands.

If you have ATF in the area of the TCM plug it has been reported that carburetor cleaner works to clean things up.

vic
 

VinceP

2005 158" High Roof Pass.
Kite,

Funny enough, I was driving my '05 today, and i was wondering if I had a normal behaviour, doing the EXACT same thing. Feeling kind of "Slipping@ between 2nd and 3rd. But I cannot feel any "real" slipping as if i press the accelerator, the car goes in gear and no slippage. It really reminds me of a TC lockup engaging. Kinda weird. My tranny has been rebuilded at 225K Kms, 3 years ago. I am due for a Tranny service, so I'll see how it behaves after that.
 

SprinterSnale

'05 T1N 3500 - NorCalSprinterCampout
I did not replace the conductor plate yet, because I pulled the electrical connector out of the tranny and discovered 20 drops of oil wetness within. (I did not want to pull it that until a new seal was on hand). This connector seal has 29K on it. Sprayed contact cleaner in loom side connector then dried with compressed air and carefully wicked out the oil of the tranny side. Loom wires all measured typical resistances.
Put it back together, cleared codes, and 'sensor 3 data' appears to be functioning correctly and feels smooth the first 50 miles of local driving. Longer driving will shed light, but with all the thread warnings about replacing the conductor plate only if absolutely necessary, it will be interesting to see if this bit of oil was causing my blues. It seems plausible.
 
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kite

Member
Kite,

Funny enough, I was driving my '05 today, and i was wondering if I had a normal behaviour, doing the EXACT same thing. Feeling kind of "Slipping@ between 2nd and 3rd. But I cannot feel any "real" slipping as if i press the accelerator, the car goes in gear and no slippage. It really reminds me of a TC lockup engaging. Kinda weird. My tranny has been rebuilded at 225K Kms, 3 years ago. I am due for a Tranny service, so I'll see how it behaves after that.

VinceP - thanks for the reply. It's not a great feeling, right? Did it just start happening?
I'm still curious if others are just used to this behavior or if it's abnormal.

Since I posted, I performed a tranny service, and cleaned the speed sensors. Symptom 2 from my first post did improve (not 100% fixed). Symptom 1 (what you're feeling) didn't change noticeably.

I found what I think is some friction material and metal chips on the filter. From what I've seen in other posts the metal might be acceptable. The bits that might be clutch don't give me much hope. Anyone have thoughts?
photo attached
 

Attachments

Midwestdrifter

Engineer In Residence
Looks like a typical filter contents.

I have done some reading, and nag1 trans use a multi-port plunger to regulate flow in the main oil circuit. This can wear resulting in non optimal tc clutch behavior and or lag. User jackbombay installed an aftermarket kit (new plunger) which he reports improved his trans behavior, and solved a persistent smoke on take off issue. It might be worth searching for his thread.

My van also has a delay/lag in 2/3 where the tc clutch is slow to switch from coast to accel slip ratio.
 

kite

Member
midwestdrifter - Thanks for the tip about the regulator valve spring thread. Interesting indeed - I wish I'd known before I had the valve body out! It would have been a no-brainer to try it.

Looks like a typical filter contents.
I think you mean this is not normal. Please confirm.


My van also has a delay/lag in 2/3 where the tc clutch is slow to switch from coast to accel slip ratio.
Does this mean you get a little flare when you step on the gas after coasting?
 

Midwestdrifter

Engineer In Residence
midwestdrifter - Thanks for the tip about the regulator valve spring thread. Interesting indeed - I wish I'd known before I had the valve body out! It would have been a no-brainer to try it.


I think you mean this is not normal. Please confirm.



Does this mean you get a little flare when you step on the gas after coasting?
Your filter contents appear normal. Not concerning. Unless I am missing a thick coating of brown clutch material? Is such a buildup present?

I do get a bit of an rpm rise under some circumstances. It takes half a second for the tc clutch control circuit to ramp up pressure I think. :idunno:
 

kite

Member
Unless I am missing a thick coating of brown clutch material? Is such a buildup present?
No sludgy coating on the filter. The fluid definitely had a brown tinge but hadn't clogged the filter so I don't think it's what you were referring to. (see photos).

What about a shift improver kit. I see them listed on rock auto.
Just learned about it yesterday, and am considering it! I'll report back if I do it, and if things improve.
 

Attachments

Midwestdrifter

Engineer In Residence
A friend did the kit, and reports it improved his van (200k+ miles) performance substantially. Mostly related to poor TC clutch take up.
 

Spendlove57

New member
The electrical board can now be unclipped(2 push clips) and separated from the valve body.
I have everything apart right now and I can not figure out where these "push clips" are to get the board off. Can someone please help before the walmart security throws me out of this parking lot pleaase! haha thanks.
 

SprinterSnale

'05 T1N 3500 - NorCalSprinterCampout
Replaced the conductor plate 2500 miles ago on the 05 T1N at 188,000. The transmission has shifted great ever since. Holds in low gears up grades longer before up-shifting and automatically downshifts earlier relative to engine load. (though I still manually downshift to 4th often). It seems to have adapted better to my driving style and the rumble strip noise (RSN) also improved.
I never conducted the conductor plate autopsy, but the visual inspection showed iron filing build up and browned leads that I suspect were losing resistance and/or solid contact where the solenoids poke into the leads.
 

Aqua Puttana

Poly - Thread Finder
A couple updates.

#1
I was performing this service to try and correct some issues I've been having and during disassembly I cracked one of the plastic solenoid covers on the valve body. Does anyone know where I can find a replacement? More info and photos here: https://sprinter-source.com/forum/showpost.php?p=775461&postcount=1
The thread that Troll [Not "The Troll"] directed to ultimately revealed that the cracked plastic covers in question were deleted on newer OEM replacement parts. The covers are not needed.

#2

There is a DIY method to check that the transmission solenoids are functioning over and above just checking the coil ohms.

Thanks goes to BenJohnson, and of course the Youtube video guy. :thumbup:

Transmission Valve Body - "pressure" test those solenoids!
https://sprinter-source.com/forum/showthread.php?t=76805

:cheers: vic
 

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