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 > General Truck Forums > All 4x4 Tech & Off Roading

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 10-04-2017, 10:31 PM   #1
70K10Hunter
Registered User
 
70K10Hunter's Avatar
 
Join Date: Jun 2012
Location: Hill Country
Posts: 435
NP 203 to NP205

K so I've been scouring the threads on this and it appears to be straight forward just want to double check my info.....I have a 77 GMC 3/4 4x4 it currently has a 203 bolted to a TH350 I am getting a 205 that was bolted to a th350. Can I use my existing transfer case cross member? I'm assuming that I will have to move it back a bit. What about drive shafts?
70K10Hunter is offline   Reply With Quote
Old 10-05-2017, 06:27 PM   #2
Undone
Registered User
 
Join Date: Aug 2010
Location: commerce ga
Posts: 894
Re: NP 203 to NP205

Cross member will work front driveshaft needs to be shorter and rear longer.
Undone is offline   Reply With Quote
Old 10-05-2017, 10:04 PM   #3
sweetk30
Registered User
 
sweetk30's Avatar
 
Join Date: May 2012
Location: horseheads,ny rust belt
Posts: 2,794
Re: NP 203 to NP205

also make sure you get shifter parts . and adapters are t-case specific as with trans .

dont forget the female to female coupler sleeve for the 205 .
__________________
77-k30lb BIG truck build .
87-k30lb budget beater build .
85-k30lb the plow machine build .
85-c10sb summer fun toy .
-----------------------------
HOLLEY SNIPER efi = worst case of p.i.t.a i ever had .

EDELBROCK pro flo 4 = best deal going so far . love my setup works great.
sweetk30 is offline   Reply With Quote
Old 10-05-2017, 11:02 PM   #4
franken
Registered User
 
Join Date: Jun 2013
Location: Somewhere
Posts: 3,052
Re: NP 203 to NP205

Make a doubler out of the 203 range box...
franken is offline   Reply With Quote
Old 10-06-2017, 07:02 PM   #5
70K10Hunter
Registered User
 
70K10Hunter's Avatar
 
Join Date: Jun 2012
Location: Hill Country
Posts: 435
Re: NP 203 to NP205

Quote:
Originally Posted by sweetk30 View Post
also make sure you get shifter parts . and adapters are t-case specific as with trans .

dont forget the female to female coupler sleeve for the 205 .

I am getting the shifter, trans output coupler/adapter, and box.
the box I'm getting was already coupled to a TH350.
So I think I'm good.
70K10Hunter is offline   Reply With Quote
Old 10-07-2017, 10:59 AM   #6
abig84
Registered User
 
abig84's Avatar
 
Join Date: Jan 2017
Location: wheaton IL
Posts: 659
Re: NP 203 to NP205

is it evengoing to bolt up? the adapter for the np203 is like a 1/4 inch thick where as the 205 is a few inches thick the transmission output shaft is going to be way to short

i wanted to run a np208 after i threw out my np203. i just brought the trans to a shop and had a longer output shaft installed
abig84 is offline   Reply With Quote
Old 10-07-2017, 11:08 AM   #7
70K10Hunter
Registered User
 
70K10Hunter's Avatar
 
Join Date: Jun 2012
Location: Hill Country
Posts: 435
Re: NP 203 to NP205

I guess I will find out when it gets here. If it is too short I will get a different one and install it when I rebuild the tranny.
70K10Hunter is offline   Reply With Quote
Old 10-07-2017, 05:25 PM   #8
sweetk30
Registered User
 
sweetk30's Avatar
 
Join Date: May 2012
Location: horseheads,ny rust belt
Posts: 2,794
Re: NP 203 to NP205

th350 with 203 or 205 use same output shaft length in trans .

the 208 and 241 used another length .
__________________
77-k30lb BIG truck build .
87-k30lb budget beater build .
85-k30lb the plow machine build .
85-c10sb summer fun toy .
-----------------------------
HOLLEY SNIPER efi = worst case of p.i.t.a i ever had .

EDELBROCK pro flo 4 = best deal going so far . love my setup works great.
sweetk30 is offline   Reply With Quote
Old 10-10-2017, 11:59 PM   #9
El Dorado Jim
Registered User
 
Join Date: Dec 2009
Location: El Dorado Ca
Posts: 3,374
Re: NP 203 to NP205

it will bolt right up, you will need to move your crossmember and redrill holes in the frame if i remember right, I did this same conversion 30 years ago.
El Dorado Jim is offline   Reply With Quote
Old 10-11-2017, 06:32 PM   #10
70K10Hunter
Registered User
 
70K10Hunter's Avatar
 
Join Date: Jun 2012
Location: Hill Country
Posts: 435
Re: NP 203 to NP205

Quote:
Originally Posted by El Dorado Jim View Post
it will bolt right up, you will need to move your crossmember and redrill holes in the frame if i remember right, I did this same conversion 30 years ago.

Yes fully figured on that, my frame on my 77 like my 70K10 has 2 brackets just aft of the existing cross member on each side with a bolt already in one hole. I think that is where the CM will go. We'll see.
That actually got me thinking I wonder if a drive shaft out of a early 70, 71, 72 K10 or 20 would work???
70K10Hunter is offline   Reply With Quote
Old 10-14-2017, 11:19 AM   #11
abig84
Registered User
 
abig84's Avatar
 
Join Date: Jan 2017
Location: wheaton IL
Posts: 659
Re: NP 203 to NP205

Quote:
Originally Posted by sweetk30 View Post
th350 with 203 or 205 use same output shaft length in trans .

the 208 and 241 used another length .
interesting. like i said in the previous post my np203 adapter is like 3/4 inch thick the adapter i have attached to a np205 is like 4 inches thick, but its for a th400transmission

i just remember trying to put a np208 onto a th350 and that out put shaft was no where near long enough, just had a trans shop put one in.

didnt know it was a different situation with the 205s and th350. learn something new everyday
abig84 is offline   Reply With Quote
Old 10-14-2017, 02:17 PM   #12
sweetk30
Registered User
 
sweetk30's Avatar
 
Join Date: May 2012
Location: horseheads,ny rust belt
Posts: 2,794
Re: NP 203 to NP205

yes th305 203/205 same output on trans .

th400 203 is short output on trans .

th400 205 is 2 diffrent output shafts for the fig8 style short input 205 or the round 6 long input 205 .
__________________
77-k30lb BIG truck build .
87-k30lb budget beater build .
85-k30lb the plow machine build .
85-c10sb summer fun toy .
-----------------------------
HOLLEY SNIPER efi = worst case of p.i.t.a i ever had .

EDELBROCK pro flo 4 = best deal going so far . love my setup works great.
sweetk30 is offline   Reply With Quote
Old 10-19-2017, 10:10 PM   #13
70K10Hunter
Registered User
 
70K10Hunter's Avatar
 
Join Date: Jun 2012
Location: Hill Country
Posts: 435
Re: NP 203 to NP205

got my Tcase the other day I will check for fit this weekend after I pull the cab.
70K10Hunter is offline   Reply With Quote
Old 10-22-2017, 12:09 AM   #14
70K10Hunter
Registered User
 
70K10Hunter's Avatar
 
Join Date: Jun 2012
Location: Hill Country
Posts: 435
Re: NP 203 to NP205

So I pulled my cab today and then pulled the 203. The 205 bolted right up to my tranny no mods needed. Before I pulled anything I marked the location of the front of the trans with a straight edge then mounted everything, used same mounts and did not need to move the cross member. Its all good, now just need to do the drive shafts.
70K10Hunter is offline   Reply With Quote
Old 10-22-2017, 12:23 PM   #15
snj8198
Registered User
 
snj8198's Avatar
 
Join Date: Feb 2007
Location: Star Valley, WY
Posts: 2,038
Re: NP 203 to NP205

what's the length difference between the 203 and now the 205?
__________________
Steve
1971 GMC Longbox. Full Roller Stroker 489 w/ FiTech EFI, Chris Straub Cam/NV4500/205/D60/14B w. Grizzly Locker and 4.11's. 2" Lift on 33's
snj8198 is offline   Reply With Quote
Old 10-22-2017, 03:07 PM   #16
70K10Hunter
Registered User
 
70K10Hunter's Avatar
 
Join Date: Jun 2012
Location: Hill Country
Posts: 435
Re: NP 203 to NP205

the 203 is 22 1/4" and the 205 is 16" from mounting face to trans and to center on rear yoke.
so 6 1/4".
70K10Hunter is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

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 10:04 AM.


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