Nag1 TECH ALERT

[abittenbinder]

-Has your Sprinter clocked over 80K miles?
-Does your Sprinter see severe "stop and go" service and clocked 50K miles?

If you answered yes to either question-I recommend you perform this additional procedure during your routine ATF fluid/filter change.


**********************
Updated info from Doktor A. Added by AP November 2017.

...
Unless you have symptoms my recommendation would be to leave things alone. There are possible pitfalls to messing with the conductor plate and cleaning. Even Doktor A backed away from his periodic cleaning recommendation.

If you have no symptoms I would do a TC/pan drain, filter, and refill with proper transmission fluid.

vic

Yes! Save the cleaning of the speed sensors and electrical board for serious symptoms only.

Doktor A

**************************

-Are you experiencing transmission related malfunction codes and/or symptoms of transmission malfunction despite having proper fluid level?

-Is your dealer recommending a transmission replacement?

If you answer yes to either of the last 2 questions-don't wait. Perform this procedure immediately.

Here's the procedure that has benefited "severe service" delivery fleets and I'm hoping will help group owners avoid needless transmission replacement.

If you answered yes to any of the above questions- I recommend you drop your transmission valve body (or as DC calls it ,"the electro-hydraulic unit"). It's simple to do and I'm recommending dropping it specifically for inspection and cleaning of the 2 circuit board mounted speed sensors.

Here's the procedure-When you have the pan off and the fluid drained (and inspected) and the filter removed-don't throw out the old filter just yet. It's halves can be uncrimped with a channel-lock plier and you can examine the inner filter media for unusual debris and accumulation.

Next -now is a good time to replace your trans elec. connector's socket O-rings since the socket needs to come out for valve body removal. Remove the small heat shield and disconnect the trans. elect connector. Reach into the trans. mounted elec. socket with a 7mm 1/4 drive socket at the end of a short extension-unbolt the retaining bolt and gently pull the socket out of the trans. Have a new socket with o-rings ready for later reassembly-part# is 68021352AA (inexpensive and comes complete with the latest black O-rings).

Now, using the same T-30 Torx bit, you used to remove the pan- loosen all the bolts and remove all but 2 (opposing bolts) holding the valve body in place. Supporting the valve body carefully-remove the last 2 bolts and lower the valve body down and carry it immediately into your surgically clean(?) workshop.

Lay the complete valve body on a clean newspaper- elec side up. Refer to your workshop manual diagrams- the speed sensors are easy to spot(on top) and should be carefully cleaned of accumulated metallic filings(they are strong magnets).

Inspect exposed parts of the circuit board and exterior of the solenoids for heavy accumulation-clean carefully.

If things look really clean- you don't need to go further. Skip down to re-installation.

If there's heavy accumulation of metallic debris you can unbolt(again-the T-30 Torx bit) the solenoid retainers and carefully remove the solenoids. The electrical board can now be unclipped(2 push clips) and separated from the valve body.

Inspect the small filter screens under the 2 regulating solenoids(If you find the screens clogged-I would stop here and seriously consider a transmission overhaul-this is thankfully rare) also inspect the o-rings on the 3 shift solenoids and single TCC lock-up solenoid(yes-part of the RSN gang). The o-rings are NOT avialable as (separate from solenoid) replacement parts from DC but any suspect o-rings can be replaced by visiting the local autoparts store and sorting through their collection of quality viton o-ring drawers.

If the circuit board looks hopelessly contaminated -it is available as a replacement part and is somewhat reasonable in price. It's mostly encased in plastic and cleaning can be tedious.

Reassemble the electro and hyd. portions and follow torque specs(71 in/lbs.) for the solenoid retainers.

Carefully lift the assembled valve body back into the transmission sump and make sure you engage the plastic sliding lever of the selector valve into the detent plate post. Torque the 10 bolts to 71 in./lbs. Install your new connector socket, and your new filter and sump seal. Bolt on the sump and fill as usual (I assume you have also drain the torque converter as per previous post). Photos show-1) The complete valve body. 2)Transmission w/valve body removed. 3)Close-up of speed sensors. 4)Disassembled valve body.5)Close-up of the TCC lock-up solenoid. 2008 Copyright by Doktor A

 

[jdcaples]

...

If there's heavy accumulation of metallic debris you can unbolt(again-the T-30 Torx bit) the solenoid retainers and carefully remove the solenoids. The electrical board can now be unclipped(2 push clips) and separated from the valve body.

...

If the circuit board looks hopelessly contaminated -it is available as a replacement part and is somewhat reasonable in price. It's mostly encased in plastic and cleaning can be tedious.

Thanks for the excellent write-up, Doktor A.

What is the source of the contamination? Is this entirely T1N-specific, or all Nag1-transmissions?

Would the system benefit from additional filtration, like a by-pass filter on the trans-cooler lines?

-Jon

 

[kurt]

-Has your Sprinter clocked over 80K miles?
-Does your Sprinter see severe "stop and go" service and clocked 50K miles?

If you answered yes to either question-I recommend you perform this additional procedure during your routine ATF fluid/filter change.

-Are you experiencing transmission related malfunction codes and/or symptoms of transmission malfunction despite having proper fluid level?

-Is your dealer recommending a transmission replacement?

If you answer yes to either of the last 2 questions-don't wait. Perform this procedure immediately.

Here's the procedure that has benefited "severe service" delivery fleets and I'm hoping will help group owners avoid needless transmission replacement.

If you answered yes to any of the above questions- I recommend you drop your transmission valve body (or as DC calls it ,"the electro-hydraulic unit"). It's simple to do and I'm recommending dropping it specifically for inspection and cleaning of the 2 circuit board mounted speed sensors.

Here's the procedure-When you have the pan off and the fluid drained (and inspected) and the filter removed-don't throw out the old filter just yet. It's halves can be uncrimped with a channel-lock plier and you can examine the inner filter media for unusual debris and accumulation.

Next -now is a good time to replace your trans elec. connector's socket O-rings since the socket needs to come out for valve body removal. Remove the small heat shield and disconnect the trans. elect connector. Reach into the trans. mounted elec. socket with a 7mm 1/4 drive socket at the end of a short extension-unbolt the retaining bolt and gently pull the socket out of the trans. Have a new socket with o-rings ready for later reassembly-part# is 68021352AA (inexpensive and comes complete with the latest black O-rings).

Now, using the same T-30 Torx bit, you used to remove the pan- loosen all the bolts and remove all but 2 (opposing bolts) holding the valve body in place. Supporting the valve body carefully-remove the last 2 bolts and lower the valve body down and carry it immediately into your surgically clean(?) workshop.

Lay the complete valve body on a clean newspaper- elec side up. Refer to your workshop manual diagrams- the speed sensors are easy to spot(on top) and should be carefully cleaned of accumulated metallic filings(they are strong magnets).

Inspect exposed parts of the circuit board and exterior of the solenoids for heavy accumulation-clean carefully.

If things look really clean- you don't need to go further. Skip down to re-installation.

If there's heavy accumulation of metallic debris you can unbolt(again-the T-30 Torx bit) the solenoid retainers and carefully remove the solenoids. The electrical board can now be unclipped(2 push clips) and separated from the valve body.

Inspect the small filter screens under the 2 regulating solenoids(If you find the screens clogged-I would stop here and seriously consider a transmission overhaul-this is thankfully rare) also inspect the o-rings on the 3 shift solenoids and single TCC lock-up solenoid(yes-part of the RSN gang). The o-rings are NOT avialable as (separate from solenoid) replacement parts from DC but any suspect o-rings can be replaced by visiting the local autoparts store and sorting through their collection of quality viton o-ring drawers.

If the circuit board looks hopelessly contaminated -it is available as a replacement part and is somewhat reasonable in price. It's mostly encased in plastic and cleaning can be tedious.

Reassemble the electro and hyd. portions and follow torque specs(71 in/lbs.) for the solenoid retainers.

Carefully lift the assembled valve body back into the transmission sump and make sure you engage the plastic sliding lever of the selector valve into the detent plate post. Torque the 10 bolts to 71 in./lbs. Install your new connector socket, and your new filter and sump seal. Bolt on the sump and fill as usual (I assume you have also drain the torque converter as per previous post). Photos show-1) The complete valve body. 2)Transmission w/valve body removed. 3)Close-up of speed sensors. 4)Disassembled valve body.5)Close-up of the TCC lock-up solenoid. 2008 Copyright by Doktor A[/QUOTE

Doctor A

No blah blah blah or BS excellent and best posting I've seen on this forum for a long time thanks.
Already bought the connector socket $12 and was recommended (MB service tech).

Upscale made my first transmission oil and filter change at 55K,now close to 100 000K will execute my next oil and filter change myself,see below why.

<<<<My experience with Upscale !!!!!!

<<<<Simple transmission service,oil and filter change.

<<<<There are 6 transmission oilpan retainers,2 where missing,2 of the remaining retainers where <<<<loose.The 2 rubber bellhousing covers missing (provide exes to Torqe Converter oil drain plug)

<<<<After 3 trips (4hr driving and $30 in diesel) to retrieve all missing
<<<<parts the arrogant """BITCH""" behind the counter told me,"ACT OF GOD"
<<<<not there fault.

 

[northener]

Kurt: could you please name the dealership that gave such poor service. We need to pin point stealership problems as well as vehicle problems.I wander about quite a bit but some areas like south Florida offer many choices. Thanks paul

 

[kurt]

Kurt: could you please name the dealership that gave such poor service. We need to pin point stealership problems as well as vehicle problems.I wander about quite a bit but some areas like south Florida offer many choices. Thanks paul

Sorry Paul but Upscale is not a dealership,a independent autoshop in Portland,Oregon specializing in German cars including Sprinters. Positively and continuously pluging itself on all Sprinter forums.

Happy day to you.

Kurt.

 

[kurt]

Kurt: could you please name the dealership that gave such poor service. We need to pin point stealership problems as well as vehicle problems.I wander about quite a bit but some areas like south Florida offer many choices. Thanks paul

To add to your posting I use *****http://www.fivestardealers.com/rontonkin/Dodge/en_us/website?adid=u&pid=u&daaXmlPath=&bid=&rid=u ****and always got service and courtesy.

 

[tegimr]

To add to your posting I use *****http://www.fivestardealers.com/rontonkin/Dodge/en_us/website?adid=u&pid=u&daaXmlPath=&bid=&rid=u ****and always got service and courtesy.

Kurt - just curious: you use and are happy with Ron Tonkin; but went to Upscale instead, and since unhappy with Upscale you are now going to do the work yourself. I'm not certain that I can follow your point. Why not return to Ron Tonkin?

Tim

 

[bikerjoe]

That is some scary looking stuff. I don't know if I am brave enough to get into my tranny like that just yet.

 

[abittenbinder]

Thanks for the excellent write-up, Doktor A.

What is the source of the contamination? Is this entirely T1N-specific, or all Nag1-transmissions?

Would the system benefit from additional filtration, like a by-pass filter on the trans-cooler lines?

-Jon

The contamination we're most concerned with are the minute ferrous filings that can accumulate on and disrupt functioning of -the speed sensors(curiously- one in particular).

These sensors are very strong magnets and protrude directly into the trans housing chamber where all the rotating elements and friction elements are housed. The torque converter with its "lock-up"(slip mode most of the time) clutch are also prime suspects in shedding fine ferrous hairs.

There is a small, weak, magnetized grid "dropped" into the sump but these sensors are unfortunately much more effective in picking up these filings(and not by design).

This is not T1N specific. The NAG1 in the new generation has a V6 specific bellhousing but it's still an NAG1.

Filtration has benefits but also its risks-quality and integrity of plumbing and hardware being the ones I would be most concerned about. Doktor A

 

[abittenbinder]

That is some scary looking stuff. I don't know if I am brave enough to get into my tranny like that just yet.

True-this is not as simple as an engine oil filter change but it's much less intimidating than it appears.

If you're nervous about doing this procedure then why not just keep it in mind and do this inspection and cleaning -if and when you ever suffer from transmission codes or symptoms.

More importantly, don't let someone talk you into performing expensive repairs or replacing your transmission without checking this first. Speed sensor (in this case false signals) related failure codes are suggestive of serious internal problems -can be misinterpreted. Doktor A

 

[kurt]

Kurt - just curious: you use and are happy with Ron Tonkin; but went to Upscale instead, and since unhappy with Upscale you are now going to do the work yourself. I'm not certain that I can follow your point. Why not return to Ron Tonkin?

Tim

Good question:Upscale (highly recommended on many forums repeatedly) price for transmission service was 1/2 from Ron Tonkin quote,big mistake on my part """"very sorry""""

 

[abittenbinder]

The contamination we're most concerned with are the minute ferrous filings that can accumulate on and disrupt functioning of -the speed sensors(curiously- one in particular).
Doktor A

There is also the risk of the metallic filings causing problems on the circuit board connections particularly those of the solenoids. That's why I also recommend inspection and cleaning of the board and the exterior of the solenoids. Doktor A

 

[jdcaples]

There is also the risk of the metallic filings causing problems on the circuit board connections particularly those of the solenoids. That's why I also recommend inspection and cleaning of the board and the exterior of the solenoids. Doktor A

I don't know much about transmission parts; I have heard that the fluid becomes contaminated with materials which are worn off. Are all fluid contaminants iron particles, or are some non-ferrous?

If some particles are non-ferrous, does non-ferrous pollution contribute to or accellerate shedding of iron from the rotating and friction elements?

If the fluid were polished using a bypass filter, could this iron contamination effect be retarded - plumbing concerns aside.

-Jon

 

[abittenbinder]

I don't know much about transmission parts; I have heard that the fluid becomes contaminated with materials which are worn off. Are all fluid contaminants iron particles, or are some non-ferrous?

If some particles are non-ferrous, does non-ferrous pollution contribute to or accellerate shedding of iron from the rotating and friction elements?

If the fluid were polished using a bypass filter, could this iron contamination effect be retarded - plumbing concerns aside.

-Jon

Since there is no combustion of fuel taking place-contamination of transmission fluid is limited to internal wear of components, and atmospheric moisture( We are assuming, of course, that there are no coolant leaks in the radiator mounted trans cooler and that you have a tight seal on your trans dipstick tube cap).

The internal contamination is both metallic (bearings, gears, and metal surfaces friction materials act against) and non metallic(primarily from friction linings). There may well be metallic constituents of the friction linings as well-I still need to take the time to cut open a tossed torque converter and inspect the torque converter clutch linings and the surface they act against.

Any form of contamination (material) will likely accelerate wear and the shedding of ferrous particles- that's why the transmission employs a filter. Will an auxiliary filter make a significant impact on wear reduction? I guess that's really a question of hardware availability, expense, design criteria(avoiding leaks, pressure drops + preventing catastrophic reduction of flow rates when contaminated)-those kinds of things. Rational fluid and filter change intervals, keeping track of leaks and repairing them, watching fluid level, using the correct spec fluid and responsible driving techniques are the best things you can now be doing to safeguard your investment. Doktor A

 

[jdcaples]

Any form of contamination (material) will likely accelerate wear and the shedding of ferrous particles- that's why the transmission employs a filter. Will an auxiliary filter make a significant impact on wear reduction? I guess that's really a question of hardware availability, expense, design criteria(avoiding leaks, pressure drops + preventing catastrophic reduction of flow rates when contaminated)-those kinds of things. Rational fluid and filter change intervals, keeping track of leaks and repairing them, watching fluid level, using the correct spec fluid and responsible driving techniques are the best things you can now be doing to safeguard your investment. Doktor A

Doktor A,

This education is both valuable and rewarding. Thank you very much for taking the time to impart guidance and information.

-Jon

 

[Bajabum]

Thanks for all the expert help and support you contribute Doktor A, you are an invaluable member of this forum. I thought it would be appropriate to post my experience here for future reference. While I was doing a transmission service on my 02' with 175K I thought I would drop the valve body for cleaning and inspection. I cleaned things up as much as possible not finding much to clean and put her back in careful to engage the plastic arm and detent. I also replace the adapter plug since there was some leakage present. I refilled the transmission with fluid and stated it up and took it for a test drive but found out it would not shift out of first gear. I had reverse and first but that was it. I went back an reread all I could and realized I did not disconnect the ground wire as you suggested.
At any rate I have gone back and serviced the transmission two more times thinking I missed something or just didn't quite get something connected properly but I have not found anything wrong and still only have first and reverse gear.
I have posted my experience at the https://sprinter-source.com/forums/showthread.php?t=2557&page=5 T1N Write-Ups but have not received any ideas as to what the problem could be or what to check other than the adapter plug and the detent in the valve body. I am positive neither of these are the problem. I hope someone with some experience and perhaps professional knowledge will offer some suggestion before I am forced to have it towed to a shop and for any future reference.

Bruce

 

[talkinghorse43]

Seems your tranny has entered into permanent limp-in mode. From the '03 service manual:

"The TCM continuously checks for electrical problems,
mechanical problems, and some hydraulic problems.
When a problem is sensed, the TCM stores a
diagnostic trouble code (DTC). Some of these codes
cause the transmission to go into 9Limp-In9 or
9default9 mode. Some DTCs cause permanent
Limp-In and others cause temporary Limp-In. The
NAG1 defaults in the current gear position if a DTC
is detected, then after a key cycle the transmission
will go into Limp-in, which is mechanical 2nd gear.
Some DTCs may allow the transmission to resume
normal operation (recover) if the detected problem
goes away. A permanent Limp-In DTC will recover
when the key is cycled, but if the same DTC is
detected for three key cycles the system will not
recover and the DTC must be cleared from the TCM
with the DRBIIIt scan tool.

Permanent Limp-In Mode
When the TCM determines there is a non-recoverable
condition present that does not allow proper
transmission operation, it places the transmission in
permanent Limp-In Mode. When the condition occurs
the TCM turns off all solenoids as well as the solenoid
supply output circuit. If this occurs while the
vehicle is moving, the transmission remains in the
current gear position until the ignition is turned off
or the shifter is placed in the 9P9 position. When the
shifter has been placed in 9P,9 the transmission only
allows 2nd gear operation. If this occurs while the
vehicle is not moving, the transmission only allows
operation in 2nd gear.

Temporary Limp-In Mode
This mode is the same as the permanent Limp-In
Mode except if the condition is no longer present, the
system resumes normal operation.
Under Voltage Limp-In Mode
When the TCM detects that system voltage has
dropped below 8.5 volts, it disables voltage-dependant
diagnostics and places the transmission in the
temporary Limp-In Mode. When the TCM senses
that the voltage has risen above 9.0 volts, normal
transmission operation is resumed.
Hardware Error Mode
When the TCM detects a major internal error, the
transmission is placed in the permanent Limp-In
Mode and ceases all communication over the CAN
bus. When the TCM has entered this mode normal
transmission operation does not resume until all
DTCs are cleared from the TCM.
Loss of Drive
If the TCM detects a situation that has resulted or
may result in a catastrophic engine or transmission
problem, the transmission is placed in the neutral
position. Improper Ratio, Input Sensor Overspeed or
Engine Overspeed DTCs cause the loss of drive.
Controlled Limp-in Mode
When a failure does not require the TCM to shut
down the solenoid supply, but the failure is severe
enough that the TCM places the transmission into a
predefined gear, there are several shift performance
concerns. For instance, if the transmission is slipping,
the controller tries to place the transmission
into 3rd gear and maintain 3rd gear for all forward
drive conditions.

EMERGENCY RUNNING FUNCTION
In order to ensure a safe driving state and to prevent
damage to the automatic transmission, the TCM
control module switches to limp-home mode in the
event of critical faults. A DTC assigned to the fault is
stored in memory. All solenoid and regulating valves
are thus de-energized.
The net effect is:
² The last engaged gear remains engaged.
² The modulating pressure and shift pressures
rise to the maximum levels.
² The torque converter lockup clutch is deactivated.
In order to preserve the operability of the vehicle
to some extent, the hydraulic control can be used to
engage 2nd gear or reverse using the following procedure:
² Stop the vehicle.
² Switch off engine.
² Move selector lever to 9P9.
² Wait at least 10 seconds.
² Start engine.
² Move selector lever to D: 2nd gear.
² Move selector lever to R: Reverse gear.
The limp-home function remains active until the
DTC is rectified or the stored DTC is erased with the
DRBt tool. Sporadic faults can be reset via ignition
OFF/ON."

While all this doesn't tell you what is wrong, it does say that there probably is a DTC (might be just a stored DTC and not current) causing permanent limp-in mode. Don't think there is a way to find out what that DTC is (or erase a stored DTC) w/o the DRB-III or equal.

 

[Don Horner]

If the TCM detects a situation that has resulted or
may result in a catastrophic engine or transmission
problem, the transmission is placed in the neutral
position. Improper Ratio, Input Sensor Overspeed or
Engine Overspeed DTCs cause the loss of drive.

This is the one that nails me at least every couple of weeks, and has been since I purchased the van with 7,000 miles on it. I bought a dipstick and monitor the fluid level pretty carefully; a change of as little as 6 ounces seems to bring on the condition. I had the fluid and filter changed at 30,000 miles which helped for about a month, then it was back to slipping into neutral. I now have 42,000 miles.

It has never caused me any permanent problems; it always happens between 40 and 60 mph, and as soon as I slow down to under 30 mph, it goes back into gear and operates normally, without a keey cycle. It can be scary, because I'm coasting until I can slow down to less than 30, and traffic is not always friendly to slowing down or pulling off.

It usually does this without throwing a visible code but occasionally the check engine light comes on, and the code as seen by my scan gauge is invariably "improper gear ratio" (P0730). That always mystifies me, because if the gear is improper, it was the transmission itself which chose it. My dealer says there are also other codes seen by the Chrysler scanner, but has not told me what they are.

It has gone into temporary limp-home (locked in 2nd gear) only twice in the 35,000 miles and it always recovers after a key cycle.

The shift into neutral always occurs when I lift the accelerator pedal. One way I have found to reduce the number of times it occurs is to accelerate more smoothly and keep a constant pressure on the pedal, then lift very gradually. It seems to not like sudden lifting of the pedal. It will also occur more frequently if I have to make a more sudden acceleration.

It happens so often, my wife no longer asks me why I'm slowing down to 30 mph in strange places.

Andy, could this be caused by the dirty sensors?

 

[talkinghorse43]

This is the one that nails me at least every couple of weeks, and has been since I purchased the van with 7,000 miles on it. I bought a dipstick and monitor the fluid level pretty carefully; a change of as little as 6 ounces seems to bring on the condition. I had the fluid and filter changed at 30,000 miles which helped for about a month, then it was back to slipping into neutral. I now have 42,000 miles.

It has never caused me any permanent problems; it always happens between 40 and 60 mph, and as soon as I slow down to under 30 mph, it goes back into gear and operates normally, without a keey cycle. It can be scary, because I'm coasting until I can slow down to less than 30, and traffic is not always friendly to slowing down or pulling off.

It usually does this without throwing a visible code but occasionally the check engine light comes on, and the code as seen by my scan gauge is invariably "improper gear ratio" (P0730). That always mystifies me, because if the gear is improper, it was the transmission itself which chose it. My dealer says there are also other codes seen by the Chrysler scanner, but has not told me what they are.

It has gone into temporary limp-home (locked in 2nd gear) only twice in the 35,000 miles and it always recovers after a key cycle.

The shift into neutral always occurs when I lift the accelerator pedal. One way I have found to reduce the number of times it occurs is to accelerate more smoothly and keep a constant pressure on the pedal, then lift very gradually. It seems to not like sudden lifting of the pedal. It will also occur more frequently if I have to make a more sudden acceleration.

It happens so often, my wife no longer asks me why I'm slowing down to 30 mph in strange places.

Andy, could this be caused by the dirty sensors?

Don't know if this could be your problem, but when new, my '02 tranny would act up (not exactly like yours, but similar) and the fix was to install a new transmission control module (TCM). The tech who did the work said some of the TCMs at that time were faulty.

 

[Bajabum]

Hum??????? What to do, what to do. The Mercedes mechanic that replaced the glow plugs told me to dump this thing, I am beginning to realize why. So turning off and turning back on is a key cycle? After reading the service manual the best I could hope for is DTC must be cleared from the TCM with the DRBIIIt scan tool.

Will the scan gauge II clear codes or does it just read them?

I'll give this a try but it sounds like hooky poky to me>

² Stop the vehicle.
² Switch off engine.
² Move selector lever to 9P9.
² Wait at least 10 seconds.
² Start engine.
² Move selector lever to D: 2nd gear.
² Move selector lever to R: Reverse gear.

Hey at this point I'll try anything. Isn't it amazing how simple jobs can turn out to be much much more than you expected or ever imagined.

Thanks for the help talkinghorse43.