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

70 RatRocket · 11-07-2002, 08:30 AM

I'm sure this has been asked before but I can't find it. I have a 70 short box 4x4, 350 engine, 350 tranny,with the dana 44 front with lock outs, GM 12 bolt rear. Someone has changed the transfer case to a 203. I lost all rear drive for some reason. (Makes a pretty good noise in transfer case too) I found a 1980 GMC long box with the orignal 350 tranny, 205 transfer case. Will this case bolt right in? Will my drive shafts bolt right back to the 205? Thanks for any info.

Blazer1970 · 11-07-2002, 08:39 AM

Pretty sure that the 203 case is longer, requiring a longer front shaft, and a shorter rear than a 205.

**JIMs70GMC** · 11-07-2002, 02:45 PM

In 1980, the NP205 has a tailshaft like the 208 and 241s. Not very desirable. If this is the case then you will not be able to use your rear driveshaft.

70 RatRocket · 11-07-2002, 06:33 PM

Today I found a transfer case from a 72 chevy. I have not seen it yet but guess it to be a 205. Would this work better with my shafts or would I still have to change them too. Or am I better off to get another 203 put in the part time converson and leave the shafts as is?

**JIMs70GMC** · 11-07-2002, 07:49 PM

I'm going to have to say that you will have to also get the tranny that came with the 205 from the 72. The tranny with your 203 is probably not the original. As for the driveshafts I'm going to differ to someone else. You could check out www.coloradok5.com or advanced adapters web site.

*MJF* · 11-08-2002, 06:14 PM

From my experience in just doing this swap, the 203 case is much longer(6"or so) than a 205. Your rear d-shaft will be too short after the swap. Not sure about the front.

On my swap, I just unbolted the 203 & adapter & bolted the 205 right up. Simple but a pain doing it by yourself.

EDIT: I just re-read your post & saw that you're talking about a 70 & a 80. I'm not sure about the differences with the body changes that happened. Mine was all 73-79 stuf that I swapped.

Tuffold72 · 11-10-2002, 07:41 PM

Make sure the 205 has a 28 spline input shaft to mate up with the th350. Personaly I like the 203 case. Mostly because of the factory 2 low option. I have yet to pop one, and they are a dime a dozen. There is a new option for converting the cases to part time. Somthing about a modified carrier that goes in place of the kit spiders that have been used for years. I think it was on off road.com that I read about it. They say that they are comparable in strength to the 205 with this mod. Just thought I would add this.

70 RatRocket · 11-11-2002, 08:55 AM

Interesting! I will have to check out that new conversion. I really don't want to have to change drive shafts in order to swap in a 205. Thanks

6869704X4 · 11-11-2002, 11:22 AM

Maybe someone on the board has the driveshaft you need. My frame and running gear are all 70 so I could take some measurements for ya.

*MJF* · 11-11-2002, 11:44 AM

OK here's more on my personal experience of changing a 203 for a 205. The rear of the 205 is shorter than a 203 so longer d-shaft will be needed.

The front is longer though. I added 2 more inches of lift along with the swap & my front d-shaft which is too short. Before the swap & lift, the slip joint was extended a few inches. After the swap. I can barely fit the d-shaft in there with it fully compressed.

Don't know if all year 203 are the same or not, but that's my experience with it.

Mike

Tuffold72 · 11-11-2002, 04:21 PM

Here is the link to that part time modification. http://www.off-road.com/chevy/mm-np203/

11-07-2002, 08:30 AM	#1
70 RatRocket Registered User Join Date: Oct 2002 Location: Nebraska Posts: 39	transfer case swap I'm sure this has been asked before but I can't find it. I have a 70 short box 4x4, 350 engine, 350 tranny,with the dana 44 front with lock outs, GM 12 bolt rear. Someone has changed the transfer case to a 203. I lost all rear drive for some reason. (Makes a pretty good noise in transfer case too) I found a 1980 GMC long box with the orignal 350 tranny, 205 transfer case. Will this case bolt right in? Will my drive shafts bolt right back to the 205? Thanks for any info.

11-07-2002, 08:39 AM	#2
Blazer1970 Registered User Join Date: Dec 1999 Location: Old Mission, MI, USA Posts: 2,510	Pretty sure that the 203 case is longer, requiring a longer front shaft, and a shorter rear than a 205. __________________ Tim

11-07-2002, 02:45 PM	#3
JIMs70GMC user # 2756 Join Date: Jun 2001 Location: Chesapeake, Virginia Posts: 4,612	In 1980, the NP205 has a tailshaft like the 208 and 241s. Not very desirable. If this is the case then you will not be able to use your rear driveshaft. __________________ 1970 K25, 8' stepside bed 350/465/205 44 up front, 60 in the rear 4.10s rolling on 33" Dunlop MTs 1986 K5, 350/465/208 Dana 60/14 bolt from a cucv 36" Super Swampers TSL/SX 1983 K20 w/ CUCV axles, 350/700R4/208 sitting on 37" Goodyears 1986 M1031 6.2 diesel, TH400/NP205 locker in the rear and a LS in the front, all stock for now..... 1986 K30, 350/400/205 dana 60 and 14 bolt. I kept the drivetrain. Body/bad and chassis are gone. 1981 K30, 350/465/205 dana 60 and dually 14 bolt. Has a G80, and a flat bed. Going to replace the flat bed. 1985 K20, 350/400/208 10 bolt and SF 14 bolt. I wonder where I can find some 1 tons. Hmmmmm Last edited by JIMs70GMC; 11-07-2002 at 02:48 PM.

11-07-2002, 07:49 PM	#5
JIMs70GMC user # 2756 Join Date: Jun 2001 Location: Chesapeake, Virginia Posts: 4,612	I'm going to have to say that you will have to also get the tranny that came with the 205 from the 72. The tranny with your 203 is probably not the original. As for the driveshafts I'm going to differ to someone else. You could check out www.coloradok5.com or advanced adapters web site. __________________ 1970 K25, 8' stepside bed 350/465/205 44 up front, 60 in the rear 4.10s rolling on 33" Dunlop MTs 1986 K5, 350/465/208 Dana 60/14 bolt from a cucv 36" Super Swampers TSL/SX 1983 K20 w/ CUCV axles, 350/700R4/208 sitting on 37" Goodyears 1986 M1031 6.2 diesel, TH400/NP205 locker in the rear and a LS in the front, all stock for now..... 1986 K30, 350/400/205 dana 60 and 14 bolt. I kept the drivetrain. Body/bad and chassis are gone. 1981 K30, 350/465/205 dana 60 and dually 14 bolt. Has a G80, and a flat bed. Going to replace the flat bed. 1985 K20, 350/400/208 10 bolt and SF 14 bolt. I wonder where I can find some 1 tons. Hmmmmm

11-08-2002, 06:14 PM	#6
MJF No longer truckless Join Date: Mar 2002 Location: Campbell, CA Posts: 299	From my experience in just doing this swap, the 203 case is much longer(6"or so) than a 205. Your rear d-shaft will be too short after the swap. Not sure about the front. On my swap, I just unbolted the 203 & adapter & bolted the 205 right up. Simple but a pain doing it by yourself. EDIT: I just re-read your post & saw that you're talking about a 70 & a 80. I'm not sure about the differences with the body changes that happened. Mine was all 73-79 stuf that I swapped. Last edited by MJF; 11-08-2002 at 06:17 PM.

11-07-2002, 06:33 PM	#4
70 RatRocket Registered User Join Date: Oct 2002 Location: Nebraska Posts: 39	Today I found a transfer case from a 72 chevy. I have not seen it yet but guess it to be a 205. Would this work better with my shafts or would I still have to change them too. Or am I better off to get another 203 put in the part time converson and leave the shafts as is?

11-10-2002, 07:41 PM	#7
Tuffold72 Registered User Join Date: Oct 2002 Location: Oregon Posts: 69	Make sure the 205 has a 28 spline input shaft to mate up with the th350. Personaly I like the 203 case. Mostly because of the factory 2 low option. I have yet to pop one, and they are a dime a dozen. There is a new option for converting the cases to part time. Somthing about a modified carrier that goes in place of the kit spiders that have been used for years. I think it was on off road.com that I read about it. They say that they are comparable in strength to the 205 with this mod. Just thought I would add this.

11-11-2002, 08:55 AM	#8
70 RatRocket Registered User Join Date: Oct 2002 Location: Nebraska Posts: 39	Interesting! I will have to check out that new conversion. I really don't want to have to change drive shafts in order to swap in a 205. Thanks

11-11-2002, 11:22 AM	#9
6869704X4 Registered User Join Date: Jul 2002 Location: SE NM Posts: 769	Maybe someone on the board has the driveshaft you need. My frame and running gear are all 70 so I could take some measurements for ya. __________________ The more I learn about women, the more I love my truck.

11-11-2002, 11:44 AM	#10
MJF No longer truckless Join Date: Mar 2002 Location: Campbell, CA Posts: 299	OK here's more on my personal experience of changing a 203 for a 205. The rear of the 205 is shorter than a 203 so longer d-shaft will be needed. The front is longer though. I added 2 more inches of lift along with the swap & my front d-shaft which is too short. Before the swap & lift, the slip joint was extended a few inches. After the swap. I can barely fit the d-shaft in there with it fully compressed. Don't know if all year 203 are the same or not, but that's my experience with it. Mike

11-11-2002, 04:21 PM	#11
Tuffold72 Registered User Join Date: Oct 2002 Location: Oregon Posts: 69	Here is the link to that part time modification. http://www.off-road.com/chevy/mm-np203/



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