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91761Duramax

Range Shift Inhibited A1000 Allison

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Yesterday I got this on notice on my truck.  No check engine light on just Range Shifted Inhibited.  I can shift From P R N.  When I shift into D nothing.  Shift into 3 and I am able to drive it.  This morning I was able to drive it on D and with in a mile of driving it stayed on 3rd gear.  While i was driving it did engage 1-5, but when i slow down it stayed at 3rd. Did some research and checked my transmission fluid level and it checked out.   Forums say it may be the NSBU Switch.  Order one from amazon hoping that maybe the problem.  Has anyone else experience this problem?  Truck is 2004 2500 HD with 175k miles. 

Edited by 91761Duramax

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Sounds like a TCM (Transmission Control Module) to me.

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Just did a quick search while here at work-

 

I would replace that range switch and when doing that check what the first tech writes- Frank Whiteman

shift range.jpg

Edited by suzukiriderx199

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id call inglewood trans. mike will tell you what's going on.. Allison is his specialty 

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few questions.

do you have anything that can read codes (regardless if the light is on or not)? tcm codes will require a high end scanner to read them

when is the last time the fluid was changed, external filter changed and the INTERNAL filter changed (miles, time at which each of those was changed)

do you run any kind of tuning in the truck?

is there ANYTHING you have done recently to the truck?

 

Edited by Chevy1925

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55 minutes ago, Chevy1925 said:

few questions.

do you have anything that can read codes (regardless if the light is on or not)? tcm codes will require a high end scanner to read them

when is the last time the fluid was changed, external filter changed and the INTERNAL filter changed (miles, time at which each of those was changed)

do you run any kind of tuning in the truck?

is there ANYTHING you have done recently to the truck?

 

3rd owner of the truck.  Bought it from my buddy.  Modification on the truck will be DSP 5 switch with 5 levels. 1. Optimize Stock ,2.Tow 3. 50ho 4. 75hp and 5. 100hp.  I have the OBD 2 Flash.  Far as I know only external filter has been changed along with the transmission oil

Edited by 91761Duramax

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try the NSBU since you already ordered it but if the problem still persists, drop the pan and take some pics of whats in the bottom of the pan BEFORE you wash it out and after you empty the fluid from it, then pull the internal filter down and take a pic if the opening where fluid would be drawn through. Have a new filter ready to pop in. then post those pics.

if that filter has never been touched, im willing to bet its plugged. the bigger tunes dont help. when it plugs up, it causes these issues and kills clutches. GM's 100k service interval was based on the 2001 dmax where the internal filter was a metal screen but they changed to the paper filter element in 2002 and never bothered to update their stuff. 30-50k service intervals are much more recommended. you cant change it too often and filters dont cost that much.

Mike L will confirm all ive stated. He knows my screen name well :bigrin

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Co Worker recommended Rancho Transmission,  only 3 miles from work, they ran the snap on scan tool and t it was not sending a signal to the scanner.  Guy told me it maybe electrical and take it to the dealership.  Drove it home and it ran through all 5 gears with no problem?   This time when I had it on drive nothing was underline until I had it on P.  NSUB should be coming in tomorrow.  Will switch that out 1st.  I wonder if moisture got into the wiring rain during the last 2 days.

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Transmission control module, has to be installed then programmed, usually by a dealer, Had it on my 09 Duramax at 140K

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Truck back normal NSUB did the trick, my neighbor ran his expensive scanner no codes were thrown.  

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I still would get that filter changed 

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3 minutes ago, I'm Sorry said:

I still would get that filter changed 

Doing full transmission oil change next pay check with 2 filters also will be Adding AFE transmission pan 

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9 minutes ago, 91761Duramax said:

Doing full transmission oil change next pay check with 2 filters also will be Adding AFE transmission pan 

Glad you got it figured out.  My opinion- don't waste the money on the deep sump pan.  It doesn't do anything but hold more fluid.  Once the trans fluid is up to operating temp there's no advantage to having more fluid.

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10 minutes ago, 91761Duramax said:

Doing full transmission oil change next pay check with 2 filters also will be Adding AFE transmission pan 

I think that's a good call on changing the pan filter..  Its pretty simple..  I would just buy a new gasket and use the stock pan..  I upgraded my trans pan and I didn't see any differences at all except that it took longer for it to get up to operating temps... 

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Unfortunately I wasted my $ on the AEM transmission already couple months ago when I had my old LLY.  Thank you for everyone for the input 

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Glad it’s fixed! Don’t freak out on these trans thinking it’s electronic. They are simple to diag and figure out.

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How difficult is it to do a transmission oil change?  My only worry is is drooping the transmission to replace the internal filter.

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6 minutes ago, 91761Duramax said:

How difficult is it to do a transmission oil change?  My only worry is is drooping the transmission to replace the internal filter.

Not difficult at all.  Only down side is there's no drain plug on the factory pan.  Drop the pan and the internal filter is right there, pull it down  to remove.  You will get splashed with fluid.  Make sure the seal comes out with the filter and you use a new seal on the new filter.  Can't remember but I think there is a magnet inside the pan so off really well before reinstalling the pan.

 

 

 

ALSFIL-2.jpg

 

 

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23 minutes ago, L.R.S. said:

Not difficult at all.  Only down side is there's no drain plug on the factory pan.  Drop the pan and the internal filter is right there, pull it down  to remove.  You will get splashed with fluid.  Make sure the seal comes out with the filter and you use a new seal on the new filter.  Can't remember but I think there is a magnet inside the pan so off really well before reinstalling the pan.

 

 

 

ALSFIL-2.jpg

 

 

They all have drain plugs in the pan. its the other GM trans that are hit or miss. 

change is as simple as any other auto. Drain the pan, drop it, if the pan has not been leaking around the gasket then reuse it, pull old filter (it will release alot of fluid, becareful), make sure old rubber seal ring is out of the VB when the filter comes out, push new filter all the way in till it stops, put pan back on and refill.

as for fill level, fill it to the cold full line, go out and drive it till the trans temp is up in the 180-200* range, then re-check the level. you want it at the BOTTOM of the hot hash marks. above that, the allison tends run hotter from windage/aeration.  

you can also do the "hoot method". guy name hoot on diesel place years ago put a how to up on how to do a full flush out of the allison from the trans cooler lines. pretty easy to do and as long as you do no more than 4-6 quarts out of the trans at a time, wont harm a thing. i do this with mine every 20-30k but i run reg dex 3 and its a built trans. 50k intervals would be ideal. Worse case, drain pan, refill, drive 20-30miles, drain again and refill and you will get about 70% of the old stuff out that way. 

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