Shift motor wont line up

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pauly

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I was in reverse and my 2003 GMC Yukon and it just stopped engine was running but it will not go anywhere in any gear I found some broken wires that go to the shift motor I was thinking maybe the transfer case slipped in the neutral and that's why I couldn't go anywhere so I just took off the shift motor without making sure it was in neutral but it's got to be in neutral or two wheel it wasn't two wheel high when it went out I got a junkyard shift motor and now I can't get the gears to line up so it'll slide on for me to install it just won't go on all the way because I can't get the gears to line up I read on the internet to get both back tires off the ground and you can turn that little gear that sticks out of the transfer case where the shift motor goes and once you get in the right spot the shift motor Will slide right on no problems I've been trying to do this for hours if anybody out there had a tip or knows a trick I would sure like to try it
 
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pauly

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I meant to say the transfer case was in two wheel high when the gears all went out I couldn't figure out how to edit it so I'm putting it here
 

justirv

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I meant to say the transfer case was in two wheel high when the gears all went out I couldn't figure out how to edit it so I'm putting it here
I myself have not seen a T-case slip into Neutral. Broken part? Sure, it might seem like Neutral. Are you sure that the trans is actually feeding power out to the T-Case? I have seen many more times where the issue was trans related. Your broken wires may be coincidental, as all was working prior to discovery. When in Reverse, the trans pressure is highest. I'm not convinced something didn't break... Sunshell perhaps? Your idea to safely put the rear on stands for demonstration can't hurt anything, if done safely and we're talking about slightly over idle speed. Hope others jump in to the conversation.
 

justirv

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I myself have not seen a T-case slip into Neutral. Broken part? Sure, it might seem like Neutral. Are you sure that the trans is actually feeding power out to the T-Case? I have seen many more times where the issue was trans related. Your broken wires may be coincidental, as all was working prior to discovery. When in Reverse, the trans pressure is highest. I'm not convinced something didn't break... Sunshell perhaps? Your idea to safely put the rear on stands for demonstration can't hurt anything, if done safely and we're talking about slightly over idle speed. Hope others jump in to the conversation.
And check for codes. Not all scanners can read TCM.
 

Fless

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I'm going to assume that you have the two-speed transfer case with an AUTO button on the dash, RPO code NP8. Is that correct?

Having assumed that, your 2003 transfer case shaft will likely be splined like this pic:

Later TCase shaft.JPG

The older transfer cases have a shaft with two flats on it, like this:

Earlier TCase shaft.JPG

Which one does your transfer case have, and does the replacement encoder motor have the correct mate? How about pics of both the new encoder motor female receptacle and the T/C shaft?

Adding @rockola1971 for comments.
 

rockola1971

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Check to make sure you have the right series (you can tell by looking at the splines or flat sides on the encoder motor) and if they are correct then here is what you do. With vehicle in park, ignition On and encoder motor plugged into chassis wiring harness but NOT installed on Tcase push your 2wd button and see if encoder motor aligns correctly on your Tcase and if it dont then pull it off the Tcase. Push 4wd HI and then try that and see if it aligns. Go through all buttons for 4wd system until you find the right one that aligns and then bolt encoder onto the Tcase.
You likely will have a splined setup like @Fless top pic he posted.

Dont forget to obtain 4wd Lo you will need to put transmission into neutral so set parking brake or block the wheels.
 
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pauly

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Check to make sure you have the right series (you can tell by looking at the splines or flat sides on the encoder motor) and if they are correct then here is what you do. With vehicle in park, ignition On and encoder motor plugged into chassis wiring harness but NOT installed on Tcase push your 2wd button and see if encoder motor aligns correctly on your Tcase and if it dont then pull it off the Tcase. Push 4wd HI and then try that and see if it aligns. Go through all buttons for 4wd system until you find the right one that aligns and then bolt encoder onto the Tcase.
You likely will have a splined setup like @Fless top pic he posted.

Dont forget to obtain 4wd Lo you will need to put transmission into neutral so set parking brake or block the wheels.
That's what I've been doing over and over again but I tried all the positions in neutral because that's where I read somewhere that that's the way you're supposed to do it but I would definitely give it a shot the way you say to do it... When I get it right will the encoder motor slide all the way on and touch the transfer case without the gasket in? Sometimes I seem to get it where it kind of goes on a little further than other times like the gears are actually lined up right and going in but when I put the gasket in I tighten it up where it's pretty tight like probably close to 10 foot pounds (on my way to the 15 foot pounds it's supposed to be) and I can feel the gasket on top and see the gasket on the bottom and there's still quite a bit of space where I can move the gasket back and forth it's still loose in there and that's when a chicken out and take it back off again I know if I keep tightening and it's not lined up right I'm going to pop that little dust cover or whatever it is off I did that on the first one I had
 
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pauly

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I'm going to assume that you have the two-speed transfer case with an AUTO button on the dash, RPO code NP8. Is that correct?

Having assumed that, your 2003 transfer case shaft will likely be splined like this pic:

View attachment 454117

The older transfer cases have a shaft with two flats on it, like this:

View attachment 454118

Which one does your transfer case have, and does the replacement encoder motor have the correct mate? How about pics of both the new encoder motor female receptacle and the T/C shaft?

Adding @rockola1971 for comments
Yeah there's a very distinct difference between the two I learned that at the wrecking yard taking them off it seems that's the only way you can tell the difference is after you take it off
 
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pauly

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I myself have not seen a T-case slip into Neutral. Broken part? Sure, it might seem like Neutral. Are you sure that the trans is actually feeding power out to the T-Case? I have seen many more times where the issue was trans related. Your broken wires may be coincidental, as all was working prior to discovery. When in Reverse, the trans pressure is highest. I'm not convinced something didn't break... Sunshell perhaps? Your idea to safely put the rear on stands for demonstration can't hurt anything, if done safely and we're talking about slightly over idle speed. Hope others jump in to the conversation.
Okay I will check and make sure that the transmission is feeding power to the transfer case power to haven't really done that and I was only putting the rear end on jack stands because it was my understanding that you could turn the little gear that's coming out of the transfer case and put it in the correct gear that way and you didn't work out I'm going to try to move the encoder motor to the right position by plugging it in and try all the positions which I have done but apparently I was doing it wrong thank you you got anything else
I myself have not seen a T-case slip into Neutral. Broken part? Sure, it might seem like Neutral. Are you sure that the trans is actually feeding power out to the T-Case? I have seen many more times where the issue was trans related. Your broken wires may be coincidental, as all was working prior to discovery. When in Reverse, the trans pressure is highest. I'm not convinced something didn't break... Sunshell perhaps? Your idea to safely put the rear on stands for demonstration can't hurt anything, if done safely and we're talking about slightly over idle speed. Hope others jump in to the conversation.

And check for codes. Not all scanners can read TCM.
It's not throwing any codes but I have a very cheap OBD2 scanner
 
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pauly

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I myself have not seen a T-case slip into Neutral. Broken part? Sure, it might seem like Neutral. Are you sure that the trans is actually feeding power out to the T-Case? I have seen many more times where the issue was trans related. Your broken wires may be coincidental, as all was working prior to discovery. When in Reverse, the trans pressure is highest. I'm not convinced something didn't break... Sunshell perhaps? Your idea to safely put the rear on stands for demonstration can't hurt anything, if done safely and we're talking about slightly over idle speed. Hope others jump in to the conversation.
Okay I will check and make sure that the transmission is feeding power to the transfer case power to haven't really done that and I was only putting the rear end on jack stands because it was my understanding that you could turn the little gear that's coming out of the transfer case and put it in the correct gear that way and you didn't work out I'm going to try to move the encoder motor to the right position by plugging it in and try all the positions which I have done but apparently I was doing it wrong thank you you got anything else
I myself have not seen a T-case slip into Neutral. Broken part? Sure, it might seem like Neutral. Are you sure that the trans is actually feeding power out to the T-Case? I have seen many more times where the issue was trans related. Your broken wires may be coincidental, as all was working prior to discovery. When in Reverse, the trans pressure is highest. I'm not convinced something didn't break... Sunshell perhaps? Your idea to safely put the rear on stands for demonstration can't hurt anything, if done safely and we're talking about slightly over idle speed. Hope others jump in to the conversation.

And check for codes. Not all scanners can read TCM.
It's not throwing any codes but I have a very cheap OBD2 scanner
Yeah there's a very distinct difference between the two I learned that at the wrecking yard taking them off it seems that's the only way you can tell the difference is after you take it off
4WD
 

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