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73-87 Chevy _ GMC Trucks => 4 Wheel Drives => Transfer Cases and Front Drivelines => Topic started by: 74ChevyK20 on March 27, 2018, 12:25:22 AM

Title: 10 spline np203 input shaft
Post by: 74ChevyK20 on March 27, 2018, 12:25:22 AM
Okay, so I’m a new member and this is my first post on the site. So my truck is, as my username suggests, a 1974 Chevy K20. The drivetrain is 350/465/203. I recently pulled the trans and transfer case to do the clutch and found the splines between the two to be almost stripped. I have access to another 465 with a good mainshaft, but I’m having a hard time finding a replacement 10 spline Input shaft for the np 203. Does anyone on here know where I can get one, or have one they do not need?
Title: Re: 10 spline np203 input shaft
Post by: Rapid Roy on March 27, 2018, 06:13:49 AM
Welcome
Title: Re: 10 spline np203 input shaft
Post by: ehjorten on March 27, 2018, 01:42:46 PM
http://offroaddesign.com/catalog/NP203%20Parts.htm
Title: Re: 10 spline np203 input shaft
Post by: 74ChevyK20 on March 27, 2018, 11:39:18 PM
Wow. If that ends up being the only place I will really need to think of speeding up my swap to a np205. That much money just for that shaft is outrageous.
Title: Re: 10 spline np203 input shaft
Post by: ehjorten on March 28, 2018, 09:40:36 AM
10 spline input gears for the NP203 have been discontinued for some time.  There is not an aftermarket source, so you have to find someone that has a used one.  You could convert your SM465 output and NP203 input to 32 spline.  You would probably spend about $600-$700 in doing so.  You could try contacting Randy's Ring and Pinion, Northwestfab, or any other some other drivetrain dealer to see if they have something laying around.
Title: Re: 10 spline np203 input shaft
Post by: blazer74 on March 28, 2018, 06:12:06 PM
203,s are still around and usually cheap due there not desired.

If your set on a 205 you will need the correct input shaft and adapter to mate the trans along with the driveshafts.
Being different lengths and your 74 should have the u bolt straps at the front T-case output  vs later years had a flange including the 205’s
A donor truck with everything is the best route if you can find one.

Squares are in the sights of  collectors now so everything is changing.
Title: Re: 10 spline np203 input shaft
Post by: 74ChevyK20 on March 28, 2018, 10:53:07 PM
My plan has always been to eventually put a 205 in it so I can do away with chain drive. And I am buying the trans from a friend, 465/205. I wanted to get the truck back together with the 203 because I didn’t know how long it would be before he was pulling it out, today I found out it will be out soon though.
Title: Re: 10 spline np203 input shaft
Post by: Irish_Alley on March 30, 2018, 06:59:23 PM
from my experience that setup should be upgraded if you plan on abusing your truck just a little. the 10 spline is weak (203 or 205) and the 1st gen yokes are another weak point where the nuts can back off and cause you to lose your front driveshaft leaving you without 4x4. even just upgrading that front yoke/output shaft is worth it but since you say your splines are damaged already then i would just replace the whole thing. if you can find a donor truck with the same wheel base and a sm465/205 then go for it. i was never able to break my trans output shaft even wheeling with 38s-44s so i wouldnt worry about a 32 spline output shaft unless you find one first or at a good price