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

67chevytodd · 01-19-2009, 12:07 AM

I have a 78 Blazer with a TH350 and NP203 (full time 4x4) transfer case combo and a 75 pickup with a Manual 4spd and a NP205 combo. I want to put the TH350 in front of the NP205, will they bolt up? I think the NP205's are stronger and have the 2HI option. Thanks Todd.

D-Monkey · 01-19-2009, 12:10 AM

I believe there is a spline difference between the 203 and the 205. A 205 connected to a 4 speed will not work. You need to find a 205 that was behind a Th350, but I hear they're somewhat rare?

67chevytodd · 01-19-2009, 12:25 AM

Any suggestion on the best transfer case to use with the TH350 that has 2HI, My wife any Kids are not fond of the clutch, would like to stay away from the full time 4x4 NP203.

D-Monkey · 01-19-2009, 12:30 AM

Quote:

Originally Posted by 67chevytodd

Any suggestion on the best transfer case to use with the TH350 that has 2HI, My wife any Kids are not fond of the clutch, would like to stay away from the full time 4x4 NP203.

I've been wondering this myself. From what I've read, best bet is this mile marker kit at the top of this list: http://www.milemarker.com/4x2conversion.html

it takes the diff out of the 203 and gives you 4Lo 2Lo N 2Hi 4Hi instead of the 4Lo Lock 4Lo N 4Hi 4Hi lock. I'm thinking about it if funds permit, either that or just track down the 205 for a Th350 :/

*edit* Your blazer is a 78, i missed that, I dunno if the kit will work as the site doesn't specify completely

84 400 · 01-19-2009, 01:03 AM

A few things here....

Spline count is going to be diffrent so with out changing the shaft in the Th350 and geting an adapter it will not bolt up. I also want to make the switch.

The Np203 is not a bad case at all and they actualy offer a lower low range then the np205. If I get my 77 in low lock that thing can climb just about anything.

The mile marker kit. There was a write up/ review on the two options they offer on coloradok5 web site. If I can find a link I will post it.

HERE IS A GREAT WRITE UP ON THE MILE MARKER KIT s INSTALL

http://www.coloradok5.com/milemarkerpt.shtml

Seems like a good option if your Np203 is in good working shape.

01-19-2009, 12:07 AM	#1
67chevytodd Junior Member Join Date: Aug 2003 Location: SW Nebraska Posts: 50	Transfer case swap??? I have a 78 Blazer with a TH350 and NP203 (full time 4x4) transfer case combo and a 75 pickup with a Manual 4spd and a NP205 combo. I want to put the TH350 in front of the NP205, will they bolt up? I think the NP205's are stronger and have the 2HI option. Thanks Todd. __________________ Old Chevys never die they are just reborn!

01-19-2009, 12:10 AM	#2
D-Monkey Registered User Join Date: Oct 2007 Location: SoCal Posts: 31	Re: Transfer case swap??? I believe there is a spline difference between the 203 and the 205. A 205 connected to a 4 speed will not work. You need to find a 205 that was behind a Th350, but I hear they're somewhat rare? Last edited by D-Monkey; 01-19-2009 at 12:11 AM.

01-19-2009, 12:25 AM	#3
67chevytodd Junior Member Join Date: Aug 2003 Location: SW Nebraska Posts: 50	Re: Transfer case swap??? Any suggestion on the best transfer case to use with the TH350 that has 2HI, My wife any Kids are not fond of the clutch, would like to stay away from the full time 4x4 NP203. __________________ Old Chevys never die they are just reborn!

01-19-2009, 01:03 AM	#5
84 400 Sb 400 club Join Date: Nov 2005 Location: NH / MA Posts: 2,746	Re: Transfer case swap??? A few things here.... Spline count is going to be diffrent so with out changing the shaft in the Th350 and geting an adapter it will not bolt up. I also want to make the switch. The Np203 is not a bad case at all and they actualy offer a lower low range then the np205. If I get my 77 in low lock that thing can climb just about anything. The mile marker kit. There was a write up/ review on the two options they offer on coloradok5 web site. If I can find a link I will post it. HERE IS A GREAT WRITE UP ON THE MILE MARKER KIT s INSTALL http://www.coloradok5.com/milemarkerpt.shtml Seems like a good option if your Np203 is in good working shape. __________________ 1984 chevy c10, built 400sb,.(SOLD) 77 K10 Project / daily driver "The Grinch" http://67-72chevytrucks.com/vboard/s...d.php?t=318363 1956 Willys Wagon (327 chevy) Project (Now Buick 225) 1980 Corvette L-48 4 speed 1992 Mustang GT built 5.0 5 speed 1985 C10 LWB Sold 1982 K10 SWB plow truck Parted out 1986 D30 M1028 fire brush truck Parted out Last edited by 84 400; 01-19-2009 at 01:04 AM.



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