350 trans to 205 transfer - The 1947 - Present Chevrolet & GMC Truck Message Board Network

llama · 08-22-2004, 08:57 AM

trying to put a newer 350 tranny to a "72" 205 transfer case. i need the adaptor and talked to advance. they say i have to change the tail shaft to a ten spline. tail shaft and adaptor $650. i'm wondering how it was done in 72? 350 trannies have not changed and i understand they are all 27 spline. all 205s are 10 spline. did the original adaptors take a 27 spline tail shaft and a 10 spline transfer case? what do i need? this problem is holding up the project, thanks for the help.

Truckstuff · 08-22-2004, 10:32 AM

Hey llama.
Not sure on the 1967 - 1972 GM Trucks. As far as I know the transmission out-put shaft always matched the in-put shaft of the transfer case, and the stock adapter is used to link them together. All the 67-72 4x4s I owned or parted out were 4spd/NP205. If you don't want go with Advance, you could look for a newer NP205. The adapters are different between the 4spd,350 and 400.

Most 1973 - 1980 GM Trucks had.
4spd/NP205 10 Spline (part time 4wd)
4spd/NP203 10 Spline (full time 4wd)
Turbo 350/NP203 27 Spline (full time 4wd)
Turbo 350/NP205 27 Spline (part time 4wd) I think, 1973 and 1980 Only
Turbo 400/NP203 32 Spline (full time 4wd)
Turbo 400/NP205 32 Spline (part Time 4wd)

Note: They all had different combinations depending on engine size and GVW.
I am running a Turbo 350 with this NP205 that came out of a 1980 3/4Ton, 350, Turbo 350.

1969 GMC · 08-22-2004, 12:46 PM

llama, you are correct that all th350's are 27 spline...and all np205's originally behind th350's have a 27 spline male input, and there is a tubular drive sleeve that mates the two together, which goes inside the adapter. I would not recommend you get the adapter you speak of, either get a different np205 from a th350, or get the 27 spline th350 input gear, and swap it in for your 10 spline. it will be cheaper.

your 10 spline np205 is from behind a pre '85 SM465 with the 10 spline output. '85 and later (K30 only) SM465's had the long 32 spline output and the 205 had a 32 spline female input gear, with no sleeve (a far superior design).

good luck

08-22-2004, 08:57 AM	#1
llama Senior Member Join Date: Jul 2002 Location: northern IL. Posts: 263	350 trans to 205 transfer trying to put a newer 350 tranny to a "72" 205 transfer case. i need the adaptor and talked to advance. they say i have to change the tail shaft to a ten spline. tail shaft and adaptor $650. i'm wondering how it was done in 72? 350 trannies have not changed and i understand they are all 27 spline. all 205s are 10 spline. did the original adaptors take a 27 spline tail shaft and a 10 spline transfer case? what do i need? this problem is holding up the project, thanks for the help.

08-22-2004, 10:32 AM	#2
Truckstuff Registered User Join Date: Dec 2003 Location: Cloverdale, British Columbia Canada Posts: 159	Hey llama. Not sure on the 1967 - 1972 GM Trucks. As far as I know the transmission out-put shaft always matched the in-put shaft of the transfer case, and the stock adapter is used to link them together. All the 67-72 4x4s I owned or parted out were 4spd/NP205. If you don't want go with Advance, you could look for a newer NP205. The adapters are different between the 4spd,350 and 400. Most 1973 - 1980 GM Trucks had. 4spd/NP205 10 Spline (part time 4wd) 4spd/NP203 10 Spline (full time 4wd) Turbo 350/NP203 27 Spline (full time 4wd) Turbo 350/NP205 27 Spline (part time 4wd) I think, 1973 and 1980 Only Turbo 400/NP203 32 Spline (full time 4wd) Turbo 400/NP205 32 Spline (part Time 4wd) Note: They all had different combinations depending on engine size and GVW. I am running a Turbo 350 with this NP205 that came out of a 1980 3/4Ton, 350, Turbo 350. Attached Images __________________ Real Trucks are Built not Bought Building: 1981 GM SB LowRider 1985 GM K3500 3+3 1981 GM K2500 SSB 1980 GM K2500 X-BC Hydro 1979 GM K3500 3+3 1976 GM K5 Blazer 1970 Custom 10 http://bc4x4.com/ Last edited by Truckstuff; 08-22-2004 at 01:06 PM.

08-22-2004, 12:46 PM	#3
1969 GMC Registered User Join Date: Feb 2003 Location: The Rubber City Posts: 5,498	llama, you are correct that all th350's are 27 spline...and all np205's originally behind th350's have a 27 spline male input, and there is a tubular drive sleeve that mates the two together, which goes inside the adapter. I would not recommend you get the adapter you speak of, either get a different np205 from a th350, or get the 27 spline th350 input gear, and swap it in for your 10 spline. it will be cheaper. your 10 spline np205 is from behind a pre '85 SM465 with the 10 spline output. '85 and later (K30 only) SM465's had the long 32 spline output and the 205 had a 32 spline female input gear, with no sleeve (a far superior design). good luck __________________ 1969 GMC K2500 1996 Honda Accord 2007 Kawasaki KLR 650



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