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Old 05-25-2023, 07:11 AM   #1
K10-Kansas
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Np203

When I shift my np203 it feels like there are 4 positions where the shift lever rests. I had assumed it would have been 2H, 2L, N, 4L, 4H but it doesn't feel that way.

I have lock/unlock hubs on the front wheels. I don't know if it has an anytime kit. How can I figure out how to work this or what's going on?
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Old 05-25-2023, 11:00 AM   #2
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Re: Np203

I had a 76 Blazer with a 203 years ago.

The Shifter plates inside were worn and gummed up with mud and dried up grease.
It made it very difficult to get it into 4wd.

My solution at the time was to make it a 2-lever shifter.

This may or may not be the issue with yours.

If you disconnect the shifter and manually shift the transfer case,
you will be able to tell if it the Transfer case causing the issue or the Shifter causing the issue.
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Old 05-25-2023, 12:18 PM   #3
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Re: Np203

The shift pattern for the NP203 (starting from the dashboard shifting rearward) is as follows;
L Loc, L, N, H, H Loc
One way to find out if you have a part time kit installed is to unlock the front hubs and leave the transfer case in either L or H. If no part time kit is installed then it will send power to the front axle, making everything turn but you won't move since the hubs are unlocked. The differential inside the 203 sends power to the wheel with the least resistance (front or rear) when the shifter is in L or H, in either of the Loc positions it will send power to both the front and rear. If you leave the hubs unlocked and shift into one of the Loc positions it should drive normally but again everything up front will be turning. There is no true 2 wheel drive with a NP203 as it left the factory. This is explained fairly well in the owners manual too.

Chances are if you have hubs on the front the transfer case has been converted with a part time kit. My understanding is with a part-time kit installed the shift pattern is changed to (front to back) 4L-2L-N-2H-4H.
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Old 05-25-2023, 08:51 PM   #4
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Re: Np203

Quote:
Originally Posted by MJN View Post
The shift pattern for the NP203 (starting from the dashboard shifting rearward) is as follows;
L Loc, L, N, H, H Loc
One way to find out if you have a part time kit installed is to unlock the front hubs and leave the transfer case in either L or H. If no part time kit is installed then it will send power to the front axle, making everything turn but you won't move since the hubs are unlocked. The differential inside the 203 sends power to the wheel with the least resistance (front or rear) when the shifter is in L or H, in either of the Loc positions it will send power to both the front and rear. If you leave the hubs unlocked and shift into one of the Loc positions it should drive normally but again everything up front will be turning. There is no true 2 wheel drive with a NP203 as it left the factory. This is explained fairly well in the owners manual too.

Chances are if you have hubs on the front the transfer case has been converted with a part time kit. My understanding is with a part-time kit installed the shift pattern is changed to (front to back) 4L-2L-N-2H-4H.
Thanks for the info. So from the factory with no loc/unlock hubs, how did the truck behave in L versus L loc?
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Old 05-26-2023, 09:55 AM   #5
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Re: Np203

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Thanks for the info. So from the factory with no loc/unlock hubs, how did the truck behave in L versus L loc?
My '74 K20 was originally a SM465/NP203 setup. Driving a manual with the 203 wasn't real fun, lots of lurching and hopping.
Anyway, in L it would essentially be 2wd low range, but again the transfer case would send the power to whichever wheel had the least traction. Typically this was a front wheel. Same as driving around in H but much slower of course.

L Loc is like driving around in 4 lo. Low range four wheel drive, front and rear axles are getting power.
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Old 05-26-2023, 01:54 PM   #6
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Re: Np203

Quote:
Originally Posted by MJN View Post
My '74 K20 was originally a SM465/NP203 setup. Driving a manual with the 203 wasn't real fun, lots of lurching and hopping.
Anyway, in L it would essentially be 2wd low range, but again the transfer case would send the power to whichever wheel had the least traction. Typically this was a front wheel. Same as driving around in H but much slower of course.

L Loc is like driving around in 4 lo. Low range four wheel drive, front and rear axles are getting power.
So in L or H, the power would go to the wheel with the least amount of traction. Does that mean that if you had a few tires stuck in the mud they'd have the least amount of traction and then they'd get the power?

Seems like it would work better to send power to the wheels that had the most traction. But I don't know if I'm understanding this correctly.
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Old 05-27-2023, 08:43 AM   #7
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Re: Np203

Quote:
Originally Posted by MJN View Post
The shift pattern for the NP203 (starting from the dashboard shifting rearward) is as follows;
L Loc, L, N, H, H Loc
One way to find out if you have a part time kit installed is to unlock the front hubs and leave the transfer case in either L or H. If no part time kit is installed then it will send power to the front axle, making everything turn but you won't move since the hubs are unlocked. The differential inside the 203 sends power to the wheel with the least resistance (front or rear) when the shifter is in L or H, in either of the Loc positions it will send power to both the front and rear. If you leave the hubs unlocked and shift into one of the Loc positions it should drive normally but again everything up front will be turning. There is no true 2 wheel drive with a NP203 as it left the factory. This is explained fairly well in the owners manual too.

Chances are if you have hubs on the front the transfer case has been converted with a part time kit. My understanding is with a part-time kit installed the shift pattern is changed to (front to back) 4L-2L-N-2H-4H.
Would there be any situation or reason to drive in L or H with hubs locked if a person for some reason had locking hubs but no part-time kit?
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Old 05-25-2023, 08:59 PM   #8
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Re: Np203

Quote:
Originally Posted by Getter-Done View Post
I had a 76 Blazer with a 203 years ago.

The Shifter plates inside were worn and gummed up with mud and dried up grease.
It made it very difficult to get it into 4wd.

My solution at the time was to make it a 2-lever shifter.

This may or may not be the issue with yours.

If you disconnect the shifter and manually shift the transfer case,
you will be able to tell if it the Transfer case causing the issue or the Shifter causing the issue.
Yeah, something weird is definitely going on because this transfer case only has 4 positions and it should definitely have 5. If i get a better look at it from under the truck will i be able to figure out what's going on?
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Old 05-25-2023, 09:14 PM   #9
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Re: Np203

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Originally Posted by K10-Kansas View Post
Yeah, something weird is definitely going on because this transfer case only has 4 positions and it should definitely have 5. If i get a better look at it from under the truck will i be able to figure out what's going on?
Let me tell you the story how I figured out at age 20.

Stuck at a Clay Pond (Becauce of a Snapped U-Joint)
One axle not pulling = You are not moving

There is plenty of info online about this now.

There is a kit like this in the link below.

You take the Spider gears out and use these Wedges to make it a Solid shaft.(Kinda)

Link:
https://www.summitracing.com/parts/mmk-501

They also make a solid shaft now.
Maybe someone else has used these.
I will try to find a link for the One piece shaft.
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Old 05-27-2023, 09:07 AM   #10
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Re: Np203

It's just AWD for day to day driving and go-anywhere readiness. I only lock mine when I get stuck or am about to get stuck. It will go through a lot of crap in just AWD.
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Old 06-16-2023, 08:33 AM   #11
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Re: Np203

After playing with this for a month I see that I can't get into H loc. When I pull the shifter all the way to the seat, I feel a click and when I let go it moves back to H. What should I do to fix this?
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Old 06-16-2023, 09:44 AM   #12
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Re: Np203

Quote:
Originally Posted by K10-Kansas View Post
After playing with this for a month I see that I can't get into H loc. When I pull the shifter all the way to the seat, I feel a click and when I let go it moves back to H. What should I do to fix this?

If you disconnect the shifter and manually shift the transfer case,
you will be able to tell if it the Transfer case causing the issue or the Shifter causing the issue.
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Old 06-16-2023, 10:00 AM   #13
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Re: Np203

Quote:
Originally Posted by Getter-Done View Post
If you disconnect the shifter and manually shift the transfer case,
you will be able to tell if it the Transfer case causing the issue or the Shifter causing the issue.
Great idea, Ill give that a shot.
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Old 06-16-2023, 10:20 AM   #14
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Re: Np203

Quote:
Originally Posted by Getter-Done View Post
I had a 76 Blazer with a 203 years ago.

The Shifter plates inside were worn and gummed up with mud and dried up grease.
It made it very difficult to get it into 4wd.

My solution at the time was to make it a 2-lever shifter.

This may or may not be the issue with yours.

If you disconnect the shifter and manually shift the transfer case,
you will be able to tell if it the Transfer case causing the issue or the Shifter causing the issue.
Quote:
Originally Posted by K10-Kansas View Post
Okay, do you open it up to spay it or is there an open spot? I assume there is since dirt can get in.

When you say you remove it to clean it thoroughly are you pulling off the whole transfer case and disassembling it partially?
Best I Recall
There are 2 bolts that hold the shifter assembly on.
you can take those out and the linkage loose then remove it.
It has a bolt on one side of the cover of the shifter assembly.
Then there is a tang that is bent to hold the other side on.
Just take some Pliers and bend this tab just enough to get the cover off.
Remember to keep up with how the levers and pieces are positioned in there.
So, you can put it back correctly.
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Old 06-16-2023, 10:26 AM   #15
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Re: Np203

Quote:
Originally Posted by Getter-Done View Post
.....Remember to keep up with how the levers and pieces are positioned in there.
So, you can put it back correctly...
I suppose that will make more sense when I pull that cover off and look in there. Would I simply take a picture so that I can youse the picture to set things as they were before replacing the cover after cleaning?
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Old 06-16-2023, 08:35 AM   #16
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Re: Np203

Hey do you lock the hubs and them move the shifter to H loc or the other way around? Does it matter?
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Old 06-16-2023, 09:21 AM   #17
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Re: Np203

The shifter has 40 years of crud in it. You can probably clean it good enough without removing it by spraying a whole can of Break Away in there while moving the lever. I usually remove it to give it a good cleaning. Then it shifts as smooth as butter and good for another 40 years.
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Old 06-16-2023, 09:59 AM   #18
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Re: Np203

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Originally Posted by cadillac_al View Post
The shifter has 40 years of crud in it. You can probably clean it good enough without removing it by spraying a whole can of Break Away in there while moving the lever. I usually remove it to give it a good cleaning. Then it shifts as smooth as butter and good for another 40 years.
Okay, do you open it up to spay it or is there an open spot? I assume there is since dirt can get in.

When you say you remove it to clean it thoroughly are you pulling off the whole transfer case and disassembling it partially?
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Old 06-16-2023, 10:13 PM   #19
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Re: Np203

Quote:
Originally Posted by K10-Kansas View Post
Okay, do you open it up to spay it or is there an open spot? I assume there is since dirt can get in.

When you say you remove it to clean it thoroughly are you pulling off the whole transfer case and disassembling it partially?
Yeah, I just remove the shifter and spray it good. I don't take the cover off the shifter or take it apart. I guess I get it clean enough without taking it apart. They sure shift nice and smooth when they are clean.
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Old 06-16-2023, 10:59 PM   #20
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Re: Np203

I have it on stands because I've been working on the brakes. I wanted to see if the 4x4 worked and also if the front brakes were now working now that I'm done replacing brake parts and adjusting things.

I locked the hubs, put it in 4 low loc, started the truck and put it in drive. I gave it some gas and the the front wheels spun. I then applied the brakes and was shocked to hear a sort of light clunk noise and assumed was the sound of the front brakes locking up. I put it in park and shut off the engine and unlocked the hubs. I then tried to return the shifter to 2 H but it is stuck. The shifter won't move. I think I'm stuck in 4 low loc.

I hope spraying the Break Away in there tomorrow fixes this.
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