questions on np 205 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

70 GMC 4x4 · 01-06-2005, 10:35 PM

Right now I have a turbo 350 and a np 203. I would like to change out the np 203 for the np 205 that I have in the garage. Will my turbo 350 bolt up to the np 205 with the correct adaptor? Is there two different styles of 350's? Short or Long shaft? I am also looking for the shifter that would go with the np 205.

Also what is involved in rebuilding a np 205? It has been sitting a while.

Thanks,
Tim

**kwmech** · 01-06-2005, 10:48 PM

There is only 1 output shaft on the 4x turbo 350, so yes with the correct adaptor it will bolt right up. You will have to redo the rear drive shaft.

784X4GUY · 01-06-2005, 10:54 PM

Quote:

Originally Posted by 70 GMC 4x4

Right now I have a turbo 350 and a np 203. I would like to change out the np 203 for the np 205 that I have in the garage. Will my turbo 350 bolt up to the np 205 with the correct adaptor? Is there two different styles of 350's? Short or Long shaft? I am also looking for the shifter that would go with the np 205.

Also what is involved in rebuilding a np 205? It has been sitting a while.

Thanks,
Tim

But yes if I am not wrong, I do believe there are two different output shaft housings on the TH350's. Oh and on the NP205 question, I have a issue of peterson's 4 wheel that they rebuilt one and it doesn't look to hard. If ya want I can take a pic of the pages and post them on here or send them to you. Oh and don't worry about pic quality, My cannon digicam is very high quality...Later Mike

70 GMC 4x4 · 01-06-2005, 10:59 PM

thanks for the info. If I rebuild it I have access to the book you are talking about, thanks though.

Tim

turkeyguide · 01-06-2005, 11:01 PM

Get yourself a Chilton manual. It will show a complete breakdown of the 205 and 203 and make rebuilding easy. There is not much that should need work. The 205 is supposed to be tough.

784X4GUY · 01-06-2005, 11:02 PM

Quote:

Originally Posted by 70 GMC 4x4

thanks for the info. If I rebuild it I have access to the book you are talking about, thanks though.

Tim

Yeah not a prob man, take it easy and good luck...Later Mike

**kwmech** · 01-06-2005, 11:38 PM

It is the 203 that is tough--I think it has about half a kabillion needle bearings in it.

soleeagle · 01-07-2005, 12:03 AM

the NP203 is chain driven and the NP205 is gear driven which makes it the better one out of the 2. The chains get slack and slop in them and become weak.

72 CustomCamper · 01-07-2005, 12:47 AM

This site should help rebuilding the 205...

Chuck

http://bulldogs-house.com/Projects/np205/

4x4Poet · 01-07-2005, 02:27 AM

Great writeup, 72CustomCamper. Thanks. Now to figure out enabling javascript on my PowerbookG4.

LKJR · 01-07-2005, 05:15 AM

no body answered your shifter question that I saw

If your not resotring this truck, I'd skip the who HA of messing with the stock shifter. Since your looking at rebuilding the unit anyway just go ahead and do a twin stick conversion on it. You'll thank yourself later. Much easier to shift, Lot less headache later if you change your mind and decided you wanted it.
the case is apart, you need a shifter, no real excuse.

**JIMs70GMC** · 01-07-2005, 08:16 AM

Has your 203 been converted to part time operation? I believe the you'll need the correct adapter and output shaft for the turbo 350, Can you find a 350/205 combo for sell in your area might be easier to do, then sell the 350/203 and your extra 205, just a thought.

poff · 01-07-2005, 12:52 PM

205s came with two or three spline counts. 10 spline for a 4 speed will not bolt up. TH400 may have had a different spline count as well.

MAC67 · 01-07-2005, 02:17 PM

yeah if i remeber right , your th400 205 is a 27 spline input sharft , the 4 spd 205 has a 10 spline input and the th350 is a 32 spline input shaft , you will need to cound the splines to see which one it is obvious if its a 4spd tranny , ive got a th350 to a 205 adapter but you will have to make sure the input shaft on your 205 is 32 spline , wish they woulda made em all the same ,

plumbcut · 01-07-2005, 05:17 PM

everybody is givin you good info- but mac67 you must be a little dyslexic

the th350 is 27 spline and the finer spline count is for the th400...

Chuck- thanks for posting that link, thats one of the best writeups ive ever seen, for ANYTHING.. . Ive been thru the 205 but its been a couple years and I wasnt as thorough as that guy was... Im needing to go thru it again because something got chewed up in mine, and boy that writeup will come in handy.. makes me wanna go tear into it right now!

pc

70 GMC 4x4 · 01-07-2005, 06:42 PM

Yep, I have a 10 spline np 205. I guess I will have to find a 32 spline 205 sometime.

Thanks alot for the info. Thank goodness I did not tear the truck apart yet!

Thanks,
TIm

poff · 01-07-2005, 08:43 PM

If you are going to rebuild it, you can change the input shaft.

**kwmech** · 01-07-2005, 10:30 PM

Quote:

Originally Posted by 70 GMC 4x4

Yep, I have a 10 spline np 205. I guess I will have to find a 32 spline 205 sometime.

Thanks alot for the info. Thank goodness I did not tear the truck apart yet!

Thanks,
TIm

You need the 27 spline not a 32. The 27 spline is a direct swap of the gear with the same bearing. the 32 spline input requires a 210n bearing which is about another 1/4'' in diameter an requires the case to be machined. The 32 spline is for the turbo 400.

70 GMC 4x4 · 01-07-2005, 10:53 PM

Is it hard to swap the out put shaft? How expensive is it?

Thanks,
Tim

**kwmech** · 01-08-2005, 01:34 AM

You need to swap the INPUT shaft of the 205 case to a 27 spline. Because of the size of the gear it has to come out the back of the case. I cannot remember how many I have done so it is easy for me. With a little patience I'm sure you could do it. Not really that hard. Probably the hardest thing would be the pocket bearing needles between the input and output gears. 17 of them I think. A brand new gear and a new bearing may run you about 175. COMPLETE gasket and seal kit--about 40 to 50.00

01-06-2005, 10:35 PM	#1
70 GMC 4x4 Registered User Join Date: Apr 2001 Location: Marion, Iowa Posts: 126	questions on np 205 Right now I have a turbo 350 and a np 203. I would like to change out the np 203 for the np 205 that I have in the garage. Will my turbo 350 bolt up to the np 205 with the correct adaptor? Is there two different styles of 350's? Short or Long shaft? I am also looking for the shifter that would go with the np 205. Also what is involved in rebuilding a np 205? It has been sitting a while. Thanks, Tim __________________ 70 3/4 GMC 4x4, 400sb

01-06-2005, 10:59 PM	#4
70 GMC 4x4 Registered User Join Date: Apr 2001 Location: Marion, Iowa Posts: 126	thanks for the info. If I rebuild it I have access to the book you are talking about, thanks though. Tim __________________ 70 3/4 GMC 4x4, 400sb

01-07-2005, 12:03 AM	#8
soleeagle Registered User Join Date: Sep 2003 Location: Shelbyville, Indiana Posts: 614	the NP203 is chain driven and the NP205 is gear driven which makes it the better one out of the 2. The chains get slack and slop in them and become weak. __________________ Chuck '85 Chevy Silverado 4X4 '91 Chevy 4X4 Suburban http://www.cardomain.com/memberpage/545941

01-07-2005, 12:47 AM	#9
72 CustomCamper huh ??? Join Date: Nov 2002 Location: Fredericksburg,Va. Posts: 3,368	This site should help rebuilding the 205... Chuck http://bulldogs-house.com/Projects/np205/ __________________ 90 Blazer Silverado 350w/ 700R4 and 32" Kelly's "I am a bomb technician. If you see me running try to keep up!"

01-07-2005, 02:27 AM	#10
4x4Poet Registered User Join Date: Nov 2004 Location: "Under Montana skies." Posts: 1,836	Great writeup, 72CustomCamper. Thanks. Now to figure out enabling javascript on my PowerbookG4. __________________ '71 GMC K20 Suburban, '71 GMC K10 Suburban, '72 Chevy C10 CST Suburban, '72 Chevy K20 clunker pickup.

01-06-2005, 10:48 PM	#2
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,659	There is only 1 output shaft on the 4x turbo 350, so yes with the correct adaptor it will bolt right up. You will have to redo the rear drive shaft.

01-06-2005, 11:01 PM	#5
turkeyguide Registered User Join Date: Jul 2004 Location: Gilbert, SC Posts: 45	Get yourself a Chilton manual. It will show a complete breakdown of the 205 and 203 and make rebuilding easy. There is not much that should need work. The 205 is supposed to be tough.

01-06-2005, 11:38 PM	#7
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,659	It is the 203 that is tough--I think it has about half a kabillion needle bearings in it.

01-07-2005, 05:15 AM	#11
LKJR Registered User Join Date: May 2000 Location: Lubbock, Tx Posts: 85	no body answered your shifter question that I saw If your not resotring this truck, I'd skip the who HA of messing with the stock shifter. Since your looking at rebuilding the unit anyway just go ahead and do a twin stick conversion on it. You'll thank yourself later. Much easier to shift, Lot less headache later if you change your mind and decided you wanted it. the case is apart, you need a shifter, no real excuse. __________________ 1st Gen Blazers Like em big and topless

01-07-2005, 08:16 AM	#12
JIMs70GMC user # 2756 Join Date: Jun 2001 Location: Chesapeake, Virginia Posts: 4,612	Has your 203 been converted to part time operation? I believe the you'll need the correct adapter and output shaft for the turbo 350, Can you find a 350/205 combo for sell in your area might be easier to do, then sell the 350/203 and your extra 205, just a thought. __________________ 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

01-07-2005, 12:52 PM	#13
poff Registered User Join Date: Dec 1999 Location: san diego, ca Posts: 546	205s came with two or three spline counts. 10 spline for a 4 speed will not bolt up. TH400 may have had a different spline count as well. __________________ '70 K-20 San Diego, CA

01-07-2005, 02:17 PM	#14
MAC67 " SHOW ME" Join Date: Jan 2003 Location: shelbyville illinois Posts: 2,624	yeah if i remeber right , your th400 205 is a 27 spline input sharft , the 4 spd 205 has a 10 spline input and the th350 is a 32 spline input shaft , you will need to cound the splines to see which one it is obvious if its a 4spd tranny , ive got a th350 to a 205 adapter but you will have to make sure the input shaft on your 205 is 32 spline , wish they woulda made em all the same ,

01-07-2005, 05:17 PM	#15
plumbcut california fill Join Date: Apr 2004 Location: Sunny So-Cal Posts: 694	everybody is givin you good info- but mac67 you must be a little dyslexic the th350 is 27 spline and the finer spline count is for the th400... Chuck- thanks for posting that link, thats one of the best writeups ive ever seen, for ANYTHING.. . Ive been thru the 205 but its been a couple years and I wasnt as thorough as that guy was... Im needing to go thru it again because something got chewed up in mine, and boy that writeup will come in handy.. makes me wanna go tear into it right now! pc

01-07-2005, 06:42 PM	#16
70 GMC 4x4 Registered User Join Date: Apr 2001 Location: Marion, Iowa Posts: 126	Yep, I have a 10 spline np 205. I guess I will have to find a 32 spline 205 sometime. Thanks alot for the info. Thank goodness I did not tear the truck apart yet! Thanks, TIm __________________ 70 3/4 GMC 4x4, 400sb

01-07-2005, 08:43 PM	#17
poff Registered User Join Date: Dec 1999 Location: san diego, ca Posts: 546	If you are going to rebuild it, you can change the input shaft. __________________ '70 K-20 San Diego, CA



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01-07-2005, 10:53 PM	#19
70 GMC 4x4 Registered User Join Date: Apr 2001 Location: Marion, Iowa Posts: 126	Is it hard to swap the out put shaft? How expensive is it? Thanks, Tim __________________ 70 3/4 GMC 4x4, 400sb

01-08-2005, 01:34 AM	#20
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,659	You need to swap the INPUT shaft of the 205 case to a 27 spline. Because of the size of the gear it has to come out the back of the case. I cannot remember how many I have done so it is easy for me. With a little patience I'm sure you could do it. Not really that hard. Probably the hardest thing would be the pocket bearing needles between the input and output gears. 17 of them I think. A brand new gear and a new bearing may run you about 175. COMPLETE gasket and seal kit--about 40 to 50.00 Last edited by kwmech; 01-08-2005 at 01:37 AM.

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