transfer case question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

robby · 09-10-2003, 11:57 PM

I just brought home my 79 K20. I has a 400 transmission and a 400 SBC. I want to keep the motor and tranny and part the rest. My question is can I use this transmission in a 69-72 Blazer? Will I need a different adapter on the transfer case? Is the transfer case I have on my 79 any good?

**MJN** · 09-11-2003, 09:11 AM

Is the '79 a full time or part time? If it is part itme four wheel drive then your transfer case should work if it's a NP205. If the transfer case if a NP203 then it won't. The NP203 will have a long aluminum housing around the tailshaft and the 205 will just come out of the back of the case. Hope this helps, also what shift pattern does it have? If it has Dash-4Lo-N-2Hi-4Hi-seat then its a 205 case.

robby · 09-11-2003, 11:01 PM

Thanks, It is a full time (no lockouts) and I am sure it is not a 205 like my 72's have. I guess what I mean is can I use the 400 tranny on a 205 case? I have another 205 but it had a manual tranny, do I need another adapter?

**MJN** · 09-11-2003, 11:14 PM

yes, the adapter will be different between the 203 and the 205, be sure to get one for an auto and a 205. The four-speed won't work it's too long. I've got one for a 350/203 but that won't work. Sorry wish I could help you with the adapter. Hope this helps a little more.

robby · 09-11-2003, 11:34 PM

Yep great, one more question. How much does an adapter for an auto to a 205 cost?

badpeanut · 09-12-2003, 12:45 AM

Correct me if I'm wrong, but a 4-speed NP205 should have a 10 spline input shaft and a TH350 requires a 27 spline shaft (a NP205 originally behind a manual won't bolt to a TH350).

**MJN** · 09-12-2003, 09:03 AM

The adapter cost depends on where you get it, I would try here first and then moveon to a junkyard or a reliable parst dealer.

badpeanut- yes your are correct teh inoput shaft ofr a manual transmission transfer case has ten slpines and the auto has 27. The input shaft on an auto t-case is also shorter than that of a manual.

**kwmech** · 09-12-2003, 09:51 PM

Quote:

Originally posted by robby
Thanks, It is a full time (no lockouts) and I am sure it is not a 205 like my 72's have. I guess what I mean is can I use the 400 tranny on a 205 case? I have another 205 but it had a manual tranny, do I need another adapter?

You will need another adaptor, you will need another transmission output shaft that is longer, and you will need the transfer case reworked to accomodate a 32 spline input gear.

robby · 09-12-2003, 10:52 PM

O.K. I think I get it now. The transfer case from a four speed can only be used with an auto if you have it reworked. If I end up with a four wheel drive that had a t350 I could use my t400, right? or are there other problems with that?

**Richard** · 09-13-2003, 01:13 AM

You might find this interesting reading. http://www.offroaddesign.com/NP205tech.htm

**MJN** · 09-13-2003, 10:05 AM

I wouldn't bother getting a t-case reworked to fit an auto, they are around and it is cheaper to just get one that can bolt up, an auto t-case will work with any auto tranny but the adapter may be different between different models.

**jamie72** · 09-13-2003, 10:48 AM

another suggetion,if your using it in a lwb just use the whole setup,there is a kit to change the 203 to a part time,and just change the length of your rear drive shaft.and a couple new bolt holes for the xmember..
there are lots of 67-72 out there with 203 in them that peolpe have comverted.
i parted a 72 jimmy with the set up,only prolbem the privios owner had was body rust...
jamie

**kwmech** · 09-13-2003, 11:20 AM

Quote:

Originally posted by robby
O.K. I think I get it now. The transfer case from a four speed can only be used with an auto if you have it reworked. If I end up with a four wheel drive that had a t350 I could use my t400, right? or are there other problems with that?

OK the 4 speed version and T350 version take the same input bearing so you can swap shafts between the 10 spline and 27 spline, BUT the t400 or 32 spline takes a larger bearing so the front of the case has to be machined accordingly, THEN you can put the 400 shaft in. All the adaptors are different. The output on the 400 trans for the 203 case is shorter than the 205 output shaft. A lot of the later model 2wd transmissions have the correct length for the 205.

*dtlilly* · 09-13-2003, 02:59 PM

I had to go to the Chevy dealer to get my adaptor for TH350/NP205 set-up. The cost was $354.58.

Non could be found around my area or even several posts on the board could not locate one.

I think Advanced Adaptors might have them. Good luck.

09-10-2003, 11:57 PM	#1
robby Semper Fidelis Join Date: Dec 2001 Location: Cedar City, Utah Posts: 654	transfer case question I just brought home my 79 K20. I has a 400 transmission and a 400 SBC. I want to keep the motor and tranny and part the rest. My question is can I use this transmission in a 69-72 Blazer? Will I need a different adapter on the transfer case? Is the transfer case I have on my 79 any good? __________________ 72 Chevy C 20 with 402 For sale 85 GMC K2500 83 Trans Am Cedar City, Utah (Missouri Native)

09-11-2003, 09:11 AM	#2
MJN Registered User Join Date: Feb 2000 Location: Maquoketa, Ia/ Orr, Mn Posts: 3,051	Is the '79 a full time or part time? If it is part itme four wheel drive then your transfer case should work if it's a NP205. If the transfer case if a NP203 then it won't. The NP203 will have a long aluminum housing around the tailshaft and the 205 will just come out of the back of the case. Hope this helps, also what shift pattern does it have? If it has Dash-4Lo-N-2Hi-4Hi-seat then its a 205 case. __________________ '51 South Bend Model "9A" '56 Chevy 3600 NAPCO '74 Chevy Cheyenne Super K20-restored on 37's '72 GMC Sierra Custom K2500- in progress '08 GMC Envoy Denali '12 GMC Sierra 2500HD Denali '17 GMC Yukon XL VCCA member #58596 http://www.nohrco.com

09-11-2003, 11:01 PM	#3
robby Semper Fidelis Join Date: Dec 2001 Location: Cedar City, Utah Posts: 654	Thanks, It is a full time (no lockouts) and I am sure it is not a 205 like my 72's have. I guess what I mean is can I use the 400 tranny on a 205 case? I have another 205 but it had a manual tranny, do I need another adapter? __________________ 72 Chevy C 20 with 402 For sale 85 GMC K2500 83 Trans Am Cedar City, Utah (Missouri Native)

09-11-2003, 11:34 PM	#5
robby Semper Fidelis Join Date: Dec 2001 Location: Cedar City, Utah Posts: 654	Yep great, one more question. How much does an adapter for an auto to a 205 cost? __________________ 72 Chevy C 20 with 402 For sale 85 GMC K2500 83 Trans Am Cedar City, Utah (Missouri Native)

09-12-2003, 10:52 PM	#9
robby Semper Fidelis Join Date: Dec 2001 Location: Cedar City, Utah Posts: 654	O.K. I think I get it now. The transfer case from a four speed can only be used with an auto if you have it reworked. If I end up with a four wheel drive that had a t350 I could use my t400, right? or are there other problems with that? __________________ 72 Chevy C 20 with 402 For sale 85 GMC K2500 83 Trans Am Cedar City, Utah (Missouri Native)

09-11-2003, 11:14 PM	#4
MJN Registered User Join Date: Feb 2000 Location: Maquoketa, Ia/ Orr, Mn Posts: 3,051	yes, the adapter will be different between the 203 and the 205, be sure to get one for an auto and a 205. The four-speed won't work it's too long. I've got one for a 350/203 but that won't work. Sorry wish I could help you with the adapter. Hope this helps a little more.

09-12-2003, 12:45 AM	#6
badpeanut Not a bad nut after all.. Join Date: Dec 2000 Location: ND Posts: 1,759	Correct me if I'm wrong, but a 4-speed NP205 should have a 10 spline input shaft and a TH350 requires a 27 spline shaft (a NP205 originally behind a manual won't bolt to a TH350).

09-12-2003, 09:03 AM	#7
MJN Registered User Join Date: Feb 2000 Location: Maquoketa, Ia/ Orr, Mn Posts: 3,051	The adapter cost depends on where you get it, I would try here first and then moveon to a junkyard or a reliable parst dealer. badpeanut- yes your are correct teh inoput shaft ofr a manual transmission transfer case has ten slpines and the auto has 27. The input shaft on an auto t-case is also shorter than that of a manual.

09-13-2003, 01:13 AM	#10
Richard Senior Member Join Date: Dec 1999 Location: Southern California Posts: 2,881	You might find this interesting reading. http://www.offroaddesign.com/NP205tech.htm __________________ Richard 1972 K10 Custom Deluxe SWB Fleetside My build https://67-72chevytrucks.com/vboard/...d.php?t=800746

09-13-2003, 10:05 AM	#11
MJN Registered User Join Date: Feb 2000 Location: Maquoketa, Ia/ Orr, Mn Posts: 3,051	I wouldn't bother getting a t-case reworked to fit an auto, they are around and it is cheaper to just get one that can bolt up, an auto t-case will work with any auto tranny but the adapter may be different between different models.

09-13-2003, 10:48 AM	#12
jamie72 Senior Member Join Date: Apr 2000 Location: madison indiana Posts: 3,836	another suggetion,if your using it in a lwb just use the whole setup,there is a kit to change the 203 to a part time,and just change the length of your rear drive shaft.and a couple new bolt holes for the xmember.. there are lots of 67-72 out there with 203 in them that peolpe have comverted. i parted a 72 jimmy with the set up,only prolbem the privios owner had was body rust... jamie __________________ jamie72 72 BB cheyenne -- Restoration getting started.. member #807 http://www.myspace.com/whitetailobsession www.antlertalk.com

09-13-2003, 02:59 PM	#14
dtlilly Account Suspended Join Date: Jan 2003 Location: Shadow of Lambeau Field Posts: 5,597	I had to go to the Chevy dealer to get my adaptor for TH350/NP205 set-up. The cost was $354.58. Non could be found around my area or even several posts on the board could not locate one. I think Advanced Adaptors might have them. Good luck.



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