The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1973 - 1987 Chevrolet & GMC Squarebody Pickups Message Board > The 1973 - 1991 Blazers, Jimmys, and Suburbans Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 09-23-2014, 04:24 AM   #1
Johhny
Registered User
 
Join Date: Sep 2014
Location: The Netherlands
Posts: 2
Unhappy NP203 input shaft swap?

Hey everyone, hope someone can help me out with this,

I got a '79 4x4 Suburban with a 400ci, th400 and a np203 transfer case. The np203 broke a while ago (worn chain) so I got myself a new one from a '78 Sub.

After removing the old np203 and installing the new one it appears to have a different input shaft. After some online research I discovered that apparently:

np203 for a th400 = 32 spline input
np203 for a th350 = 27 spline input

Since the old one only has a worn chain I was wondering if I can swap the input shaft to the new case? Did anyone did this before? What steps are needed? Will the axles still fit?

Since most Subs here are 2wd it was already hard to get a GM np203, so getting another np203 is kinda hard. If anyone knows any other solutions please let me know.

Old np203:



New np203:

Johhny is offline   Reply With Quote
Old 09-24-2014, 06:54 PM   #2
68Timber
I know the pieces fit
 
68Timber's Avatar
 
Join Date: Nov 2007
Location: MONTGOMERY, AL
Posts: 5,523
Re: NP203 input shaft swap?

I would contact Advanced Adapters, they'll know for sure, but I suspect they'll interchange. As for swapping it out, I couldn't help there, I get cross-eyed when someone takes a transfer case apart. But I'm guessing the service manual will walk you through it.
__________________
John

79 2wd Blazer (Bruiser)
85 M1009 Blazer (Sarge) build
74 Honda Z50 build
68Timber is offline   Reply With Quote
Old 09-25-2014, 03:30 AM   #3
Johhny
Registered User
 
Join Date: Sep 2014
Location: The Netherlands
Posts: 2
Re: NP203 input shaft swap?

You were correct, they do interchange. I ran into a new problem tho:

I disassembled the old np203:



took out the input drive gear (32 spline):



and placed it in the new tcase:



Everything fits perfectly but I can't seem to reassemble the range box case...

There's a lever with shaft combined with a lockout shift that's located in the range box case itself:



The lever with shaft goes on 1, the lockout shift goes on 2:



I have no idea how to connected this when putting the case on, it al has to connect when the case is already half on, anyone has any suggestions?
Johhny is offline   Reply With Quote
Reply

Bookmarks

Tags
mile marker, np203, suburban, swap, th400


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 10:05 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com