What are the NP205 case differences - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**WIDESIDE72** · 12-14-2008, 05:47 PM

I understand that the adapter between the trans andcase id different for the SM465, TH350 and TH400, but is the input spline on the t case different as well?

CPNEJR · 12-14-2008, 08:45 PM

yes i believe the splines are different depending on the tranny

lowe137 · 12-14-2008, 09:58 PM

heres some good np205 tech

http://www.4wheeloffroad.com/techart...ase/index.html

Musclerodz · 12-14-2008, 10:37 PM

10 spline input found on SM465

27 spline input found on TH350

31 spline input found on TH400

Input side bolt pattern figure 8 early style, or round late style

Output side could eaither have slip yoke or fixed yoke.

That is the abbreviated version

**kwmech** · 12-15-2008, 02:24 PM

Turbo 400 version is a 32 spline----------------31 spline is ford, 23 and 29 is dodge

**WIDESIDE72** · 12-16-2008, 05:51 PM

I went and looked at a 69 C10 with a 292 and what I think is an SM 420(?) It is the original 4 speed that came in this truck. Out of curiosity,would the SM420 take the same t case with 10 splin input as an SM465. I understand that SM465's did not come stock in 67-72 trucks (?)

1969 GMC · 12-16-2008, 07:08 PM

Quote:

Originally Posted by WIDESIDE72

I went and looked at a 69 C10 with a 292 and what I think is an SM 420(?) It is the original 4 speed that came in this truck. Out of curiosity,would the SM420 take the same t case with 10 splin input as an SM465. I understand that SM465's did not come stock in 67-72 trucks (?)

Nope, SM465's are the most common 4 speeds from about '69 or so on. There were also a few oddball NP435's, but not in 4x4.

My '69 originally had a SM465/T221 combo. The output shaft of the tranny appears to be the same for the 10 spline 465 w/ the 205. The adapters and drive sleeves for the rockwell vs. the np205 are different and unique to each t-case, though.

sweet70beast · 12-16-2008, 09:35 PM

My 71 K-20 has a 465/205 combo.

**WIDESIDE72** · 12-17-2008, 09:46 AM

Quote:

Originally Posted by 1969 GMC

Nope, SM465's are the most common 4 speeds from about '69 or so on. There were also a few oddball NP435's, but not in 4x4.

My '69 originally had a SM465/T221 combo. The output shaft of the tranny appears to be the same for the 10 spline 465 w/ the 205. The adapters and drive sleeves for the rockwell vs. the np205 are different and unique to each t-case, though.

The 69 I looked at is 2wd. I looked at it for the cab. iwas just brain storming about using the 292 and 4 speed in my 3/4 ton 4x4. I know understand that this would require a hard to find engine crossmember to usse the 292 in a 4x4. I have a 2wd 6 cylinder crossmember, but...

scott123 · 01-12-2009, 06:48 PM

just pulled the 3spd/T-221 out of my '69 with the 292 six cylinder. I had to buy another K-5 just to get the front crossmember to put the 350/350/205 in my truck. i will check to see if the mounts are still in the shop. if you are interested....s.

**special-K** · 01-12-2009, 08:50 PM

No info on the 3spd/205 combo?

shakedown96 · 01-16-2009, 05:41 PM

the sm 420 was a 47 to 67 4spd with a 7.05 to one first gear (lower than the sm 465 with 6.56).

12-14-2008, 05:47 PM	#1
WIDESIDE72 Senior Member Join Date: Aug 2008 Location: Cedar Park, Texas Posts: 7,494	What are the NP205 case differences I understand that the adapter between the trans andcase id different for the SM465, TH350 and TH400, but is the input spline on the t case different as well?

12-14-2008, 08:45 PM	#2
CPNEJR Registered User Join Date: Sep 2003 Location: Franconia,N.H. Posts: 1,029	Re: What are the NP205 case differences yes i believe the splines are different depending on the tranny __________________ (Only) Member of the CPNE Fan Club Aint that the truth 67 C-10 350 with 3-speed tranny and 308 gears swb step 82 Z28 Camaro 355 small block over 350 hp and a borg warner super t-10 (blown engine) 72 Chevy K20 Suburban (future project) 70 Chevy K20 now 68 GMC K2500 2003 Chevy 2500hd ccsb 4X4 (daily driver)

12-14-2008, 09:58 PM	#3
lowe137 Registered User Join Date: May 2008 Location: cali Posts: 43	Re: What are the NP205 case differences heres some good np205 tech http://www.4wheeloffroad.com/techart...ase/index.html Last edited by lowe137; 12-14-2008 at 09:59 PM. Reason: spelling

12-14-2008, 10:37 PM	#4
Musclerodz Senior Member Join Date: Aug 2005 Location: OKC, OK Posts: 2,365	Re: What are the NP205 case differences 10 spline input found on SM465 27 spline input found on TH350 31 spline input found on TH400 Input side bolt pattern figure 8 early style, or round late style Output side could eaither have slip yoke or fixed yoke. That is the abbreviated version __________________ Mike Redpath

12-15-2008, 02:24 PM	#5
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,460	Re: What are the NP205 case differences Turbo 400 version is a 32 spline----------------31 spline is ford, 23 and 29 is dodge

12-16-2008, 05:51 PM	#6
WIDESIDE72 Senior Member Join Date: Aug 2008 Location: Cedar Park, Texas Posts: 7,494	Re: What are the NP205 case differences I went and looked at a 69 C10 with a 292 and what I think is an SM 420(?) It is the original 4 speed that came in this truck. Out of curiosity,would the SM420 take the same t case with 10 splin input as an SM465. I understand that SM465's did not come stock in 67-72 trucks (?)

12-16-2008, 09:35 PM	#8
sweet70beast Registered User Join Date: Sep 2006 Location: Shelley Idaho Posts: 876	Re: What are the NP205 case differences My 71 K-20 has a 465/205 combo. __________________ 1970 Nova 327/T5 (my 1st car) 1971 K-20 350/350/205 (winter DD) 1953 GMC Suburban 1968 Chevy Bel Air 1976 Chev C-10 1972 Skylark (suncoupe) 1 of 3943 made

01-12-2009, 06:48 PM	#10
scott123 Registered User Join Date: Dec 2007 Location: Middleburg, North Carolina Posts: 480	Re: What are the NP205 case differences just pulled the 3spd/T-221 out of my '69 with the 292 six cylinder. I had to buy another K-5 just to get the front crossmember to put the 350/350/205 in my truck. i will check to see if the mounts are still in the shop. if you are interested....s.

01-12-2009, 08:50 PM	#11
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,862	Re: What are the NP205 case differences No info on the 3spd/205 combo? __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

01-16-2009, 05:41 PM	#12
shakedown96 Registered User Join Date: Jan 2009 Location: gilboa ny Posts: 91	Re: What are the NP205 case differences the sm 420 was a 47 to 67 4spd with a 7.05 to one first gear (lower than the sm 465 with 6.56). Last edited by shakedown96; 01-16-2009 at 05:48 PM.



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