M1078 Tranny code d14526 no speedo

[Seapup]

Good morning gents,
Got my first transmission challenge.
New truck to me,
Fluids good
Starts and Idles fine
The problems start when I put it into drive, it started down the road in chaos mode- bronco shifting and then, display shows 3 and I can not use selector buttons.
(DNS lockout I assume)
Pulled Tranny codes
d14526 (mode on)
d22522
d31313

thought I would start with first code d14526 Allison code for
“Open Circuit N Solenoid Circuit”
not sure we’re N solenoid is?
From research it appears to be the retarder solenoid?
If so we’re would said little gem be located?
Also best trouble shooting methods of this N circuit?
Any help/direction would be appreciated
Thanks

Bonus question,
also out of curiosity 3 lmtv’s with either engine/power issues all make the same exaggerated Diesil chug sound intermittently
While applying throttle.
It would basically rattle the cabin with its resonance?
(Sorry, best I could describe it)
what is this sound/resonance?
Intermittent turbo loading, maybe???

 

[fuzzytoaster]

You're in the prime position to open the TM 9-2320-365-20-2 page 2-1360 and follow the trouble shooting steps to get to know your vehicle. It's a great guide with pictures to point out parts and problems. It's probably better than we can direct you on the forum here but we can try still.

I'd recommend you check the following locations/items first:

1. Clean all battery terminals and double check all connections
2. Make sure you are getting clean 12.8v and 25.6v to the PDP (passenger dash, it has lugs to check for power)
3. Remove the cab grill and look at the transmission harness condition, they are typically dry rot if not damaged outright
4. Remove the kick panel from below the PDP and inspect wiring
5. Follow TM trouble shooting steps for pin out to isolate wire or identify solenoid issue

Engine issue wise look into servicing the fuel filter and fuel/water separator. Have you replaced the fuel lines? If not they can suck in air causing the engine to surge/be erratic.

 

[Ronmar]

All the solenoids are in the control module bolted up into the bottom of the transmisdion where the filters are located...

This as suggested could be bad wiring at the locations mentioned.

For engine issues you need to be specific on year/model of truck. The A0 and A1 have radically different engines...

 

[Seapup]

You're in the prime position to open the TM 9-2320-365-20-2 page 2-1360 and follow the trouble shooting steps to get to know your vehicle. It's a great guide with pictures to point out parts and problems. It's probably better than we can direct you on the forum here but we can try still.

I'd recommend you check the following locations/items first:

1. Clean all battery terminals and double check all connections
2. Make sure you are getting clean 12.8v and 25.6v to the PDP (passenger dash, it has lugs to check for power)
3. Remove the cab grill and look at the transmission harness condition, they are typically dry rot if not damaged outright
4. Remove the kick panel from below the PDP and inspect wiring
5. Follow TM trouble shooting steps for pin out to isolate wire or identify solenoid issue

Engine issue wise look into servicing the fuel filter and fuel/water separator. Have you replaced the fuel lines? If not they can suck in air causing the engine to surge/be erratic.

Nice!
I’m setting up a little iPad to download all the manuals on right now!!!
-
But couldn’t you have just spoonfed me the answer and solution to my problem and just one short sentence?

With no more info on my part?
~ sorry sarcasm is a way of life here

 

[Seapup]

All the solenoids are in the control module bolted up into the bottom of the transmisdion where the filters are located...

This as suggested could be bad wiring at the locations mentioned.

For engine issues you need to be specific on year/model of truck. The A0 and A1 have radically different engines...

Ahhh yes mine is an A0
Perfect thank you I suspected it would be in what would probably be similar to a valve body in one of the itty-bitty vehicles.
I will start with checking out the wiring this morning

 

[Seapup]

Ahhh yes mine is an A0
Perfect thank you I suspected it would be in what would probably be similar to a valve body in one of the itty-bitty vehicles.
I will start with checking out the wiring this morning

Quick update I went through the warn them from the front of the cab all the way to the transmission and to the sensors and it looked brand-new it wasn’t the typical white wires but had colored wires in it so I’m willing to bet that it’s been changed already as the connectors on the inside look brand-new.
I have also cleaned the connectors to the voltage box underneath the air over a hydraulic pump and next I will start taking some measurements and checking out sensors and solenoids.
I think my priority is figuring out the N solenoid and circuit as it is an active fault that will not clear.

It’s my understanding to get to that solenoid I will have to pull the pan on the bottom of the transmission and it should be in the solenoid or valve body is that correct?

 

[fuzzytoaster]

Quick update I went through the warn them from the front of the cab all the way to the transmission and to the sensors and it looked brand-new it wasn’t the typical white wires but had colored wires in it so I’m willing to bet that it’s been changed already as the connectors on the inside look brand-new.
I have also cleaned the connectors to the voltage box underneath the air over a hydraulic pump and next I will start taking some measurements and checking out sensors and solenoids.
I think my priority is figuring out the N solenoid and circuit as it is an active fault that will not clear.

It’s my understanding to get to that solenoid I will have to pull the pan on the bottom of the transmission and it should be in the solenoid or valve body is that correct?

That's correct if you're pulling it. It's not so much a pan as it's the full valve body for the transmission. You'll need to drain it and pull the filters to get as much out as you can. You will make a mess after draining it.. so be prepared. I highly recommend pulling the front drive shaft and yoke off the t-case as it gets in the way of dropping the valve body straight down. Use a transmission jack or some mechanical assistance. I've pulled 3 of these (one twice) and though it's possible to wiggle and angle it to get it out you risk pinching the harness or damaging parts on reinstall. The only thing more frustrating than dropping the valve body is doing it twice.

I still recommend ohming out the harness at the transmission pigtail before dropping the unit and sourcing a solenoid beforehand.

 

[Ronmar]

Yea I would identify the N solenoide wire pair in the transmission harness connector and confirm the short is in the transmisdion before I commitred to pulling the control module.

 

[Seapup]

That's correct if you're pulling it. It's not so much a pan as it's the full valve body for the transmission. You'll need to drain it and pull the filters to get as much out as you can. You will make a mess after draining it.. so be prepared. I highly recommend pulling the front drive shaft and yoke off the t-case as it gets in the way of dropping the valve body straight down. Use a transmission jack or some mechanical assistance. I've pulled 3 of these (one twice) and though it's possible to wiggle and angle it to get it out you risk pinching the harness or damaging parts on reinstall. The only thing more frustrating than dropping the valve body is doing it twice.

I still recommend ohming out the harness at the transmission pigtail before dropping the unit and sourcing a solenoid beforehand.

Thank you, ah should I call you Mr. fuzzy or Mr. toaster
Ok I will be ohming out the harness and pigtail before considering pulling the pan.
And exactly how heavy is this valve body? Do I really need a trans lift in order to play with the big boys on this one?
I will change out the trans filters while in there too.

 

[Seapup]

Yea I would identify the N solenoide wire pair in the transmission harness connector and confirm the short is in the transmisdion before I commitred to pulling the control module.

On it right now.

and then I will pull the ECU and check for water intrusion if the circuit test out Within specs.

 

[Seapup]

While I’ve got my hands in this bucket
I can’t seem to identify the “N” solenoid does it go under another name?
And I’m trying to source said solenoid , also if somebody has a part number for future reference. That would be niffty

 

[Ronmar]

What year is this truck?

 

[Seapup]

What year is this truck?

1998 M1078 A0 wtec2

 

[fuzzytoaster]

Thank you, ah should I call you Mr. fuzzy or Mr. toaster
Ok I will be ohming out the harness and pigtail before considering pulling the pan.
And exactly how heavy is this valve body? Do I really need a trans lift in order to play with the big boys on this one?
I will change out the trans filters while in there too.

Oh please... Mr. Toaster was my father. What ever name you want.

Attached is the location of "N Solenoid"
P/N 29507451 .SOLENOID,ELECTRICAL (N SOLENOID)
Quick google search found one: https://www.ebay.com/itm/223747169628

I believe the unit is around 65 lbs. You need 3 hands to do it as the pigtail (harness) feeds up through a hole in the transmission housing so it has to be guided as you lower the unit. Also putting it back in can be a pain as you need to go straight up as not to pinch anything and then you still have to secure it with a few bolts. If you have a soldier B laying around recruit him.

 

[Seapup]

Oh please... Mr. Toaster was my father. What ever name you want.

Attached is the location of "N Solenoid"
P/N 29507451 .SOLENOID,ELECTRICAL (N SOLENOID)
Quick google search found one: https://www.ebay.com/itm/223747169628

I believe the unit is around 65 lbs. You need 3 hands to do it as the pigtail (harness) feeds up through a hole in the transmission housing so it has to be guided as you lower the unit. Also putting it back in can be a pain as you need to go straight up as not to pinch anything and then you still have to secure it with a few bolts. If you have a soldier B laying around recruit him.

All right Mr. fuzzy it is
Just don’t ask me to say it with a straight face
Perfect thank you for the TM page
it’s exactly what I needed to see!
I’ll keep ya posted.

 

[Ronmar]

The cool thing about most mil manuals is that in the cautions before the procedure instructions they often list the component weights for the parts you will be working on...

The 3060 troubleshooting manual(includes 3070pt trans) shows the N solenoid being wired between pins H2 & H3 on the trans connector, but that was a pre 95 diagram. Havnt found the pins for N for the post 95 diag(ran out of time this morning) and am not sure if they remained on the same pins post 1995.

 

[Seapup]

The cool thing about most mil manuals is that in the cautions before the procedure instructions they often list the component weights for the parts you will be working on...

The 3060 troubleshooting manual(includes 3070pt trans) shows the N solenoid being wired between pins H2 & H3 on the trans connector, but that was a pre 95 diagram. Havnt found the pins for N for the post 95 diag(ran out of time this morning) and am not sure if they remained on the same pins post 1995.

Thanks for the info burger!
So working my way through the system, got sidetracked and geeked out on the CTIS system and found a program that I can program CTIS controllers with .
Ok so I started at the batteries
Measured 23.8v :/
Alt not charging?!
Cleaned the crud off the combiner box under the spare tire.
New Clean galvy nuts and lock washers installed and dielectric grease slathered over exposed terminals

opened up VIP? Under kick Panel looks brand new and it has 6 24v relays in it not 5… possibly mismatched part for a wtec 2 set up?
Ohmed out “N” relay from j119 connector from pin k to pin a.
Measured 3.5 ohms @ 81 degrees Fahrenheit So “N” Circuit and solenoid appears to check out from the front grill connector back to transmission

so now I move forward up the chain to the expensive stuff…
Pulling steering wheel and dash to take a looks at connectors and transmission controller

while I’m waiting for the sun to charge up my batteries I went through the relay box and found a couple mismatched and questionable relays and cleaned all contacts and installed all new blade fuses.
Picked up a fuel filter and a water fuel separator from Napa.

while waiting I put my special powers of ADHD to use and noticed the fan clutch was coming apart so I’ll be removing and inspecting that issue.

as soon as I hook fully charged batteries up I’ll trouble shoot the alternator and see if we can get it to spit lightning…
More later

 

[Seapup]

also for posterity
Part number for the “N” solenoid is
29507451
Superseded to 29545638
They are about 130 bucks for an Allison one and about 70-ish for an aftermarket.
Heads up apparently Allison is going to do a companywide 20 to 30% price increase on everything starting October 1 of this year.
But don’t worry, our fine president has this handled, we are not in a recession and no such thing as inflation…

 

[Ronmar]

2 of those relays in the VIM shouldbe 12V...

 

[Seapup]

2 of those relays in the VIM shouldbe 12V...

Your are correct sir
Took a look at it and there are two brand new shiny 12 V relays hidden among the jungle of 24 V relays