TRANNY & TRANSFER CASE QUESTION - The 1947 - Present Chevrolet & GMC Truck Message Board Network

4bynut · 02-23-2005, 05:24 AM

I'm looking at buying a 1967 K20 that still has the original 4sp. and rockwell transfer case. And what I need to know is if a NP205 that came off a 4sp. will be a direct swap. Thank's in advance Jason.

Blazer1970 · 02-23-2005, 08:12 AM

You would need to use the newer SM465/adapter/NP205 combo together. A 205 will not work with your SM420.

1969K10 · 02-23-2005, 06:08 PM

Leave the Rockwell in there, its an awesome X-fer

Prerunner1982 · 02-23-2005, 07:47 PM

man those sm420s and rockwell 221 are crap.. buy yourself the 465 and 205 and send the 420 and 221 to me... you can even pay me to take them off your hands...

1969 GMC · 02-23-2005, 08:06 PM

Quote:

Originally Posted by 1969K10

Leave the Rockwell in there, its an awesome X-fer

I don't know about "awesome" but I would just run it until it dies (and it will if you drive it...ask me how I know). Then replace it with a SM465/NP205 combo and sell the SM420 to a Jeeper.

4bynut · 02-23-2005, 09:13 PM

Thank's for the help guy's. If I end up buying the truck, I'll drive it some before I decide. The owner claims it works fine and the tranny & transfer case were rebuilt by PO. PO also installed a new clutch & pressure plate. It'll still need PB and PS added. Thank's again for the help. Jason

Americanrider · 02-23-2005, 09:52 PM

The rocks are a bit noisy at high speed, but just about bomp-proof!

4bynut · 02-25-2005, 05:24 AM

Quote:

Originally Posted by Americanrider

The rocks are a bit noisy at high speed, but just about bomp-proof!

Has anyone had any luck quieting them. Maybe using a synthetic oil or some kind of additive. Thank's again Jason

Americanrider · 02-25-2005, 01:26 PM

I used plain 'ol 80-90, but once I get the floorpan cleaned from years of neglect I'm going to undercoat the bottom of the cab. Then work on the interior floor, a liner w/ carpet would help mine a great deal. I'm running 4.56's so anything above 50 is Hi-speed for me. Next time I re-lube I'll try something better.

02-23-2005, 05:24 AM	#1
4bynut Senior Member Join Date: Mar 2004 Location: Morrison, IL Posts: 793	TRANNY & TRANSFER CASE QUESTION I'm looking at buying a 1967 K20 that still has the original 4sp. and rockwell transfer case. And what I need to know is if a NP205 that came off a 4sp. will be a direct swap. Thank's in advance Jason. __________________ 2007 Chevy 2500HD crew cab, 4x4, duramax w/Allison trans. 2001 Chevy ZR2 Ext. cab 4x4 (DD) 1967 Chevy SWB 4x4, BBC, Th400, NP205, 6" lift, and 35's (In Process) 1970 Chevy Blazer 4x4, BBC, TH400, NP241, 6" lift, and 38.5 boggers in front, 44 boggers on the rear ( mud racer project)

02-23-2005, 08:12 AM	#2
Blazer1970 Registered User Join Date: Dec 1999 Location: Old Mission, MI, USA Posts: 2,507	You would need to use the newer SM465/adapter/NP205 combo together. A 205 will not work with your SM420. __________________ Tim

02-23-2005, 06:08 PM	#3
1969K10 Senior Member Join Date: Jul 2004 Location: Clarks Hill, Indiana Posts: 733	Leave the Rockwell in there, its an awesome X-fer __________________ 1969 K10 - V8, 465, 205, 12 bolt, D44 2002-current 1969 K20 - V8, 465, 221, Eaton, D44 2012-current Nothin' but drums on all 4 corners! past horses in the stable 72 C10-short step (97-02), 68 C10-long fleet (06-12)

02-23-2005, 07:47 PM	#4
Prerunner1982 Registered User Join Date: Oct 2002 Location: Edmond, OK Posts: 5,904	man those sm420s and rockwell 221 are crap.. buy yourself the 465 and 205 and send the 420 and 221 to me... you can even pay me to take them off your hands... __________________ Jon 1982 Chevy Silverado 350/th350.... RETIRED 1993 Jeep XJ 2 door(Cherokee) 4wd 4.0ltr/AX-15 (5spd)/NP231 .... Oklahoma Roll Call

02-23-2005, 09:13 PM	#6
4bynut Senior Member Join Date: Mar 2004 Location: Morrison, IL Posts: 793	Thank's for the help guy's. If I end up buying the truck, I'll drive it some before I decide. The owner claims it works fine and the tranny & transfer case were rebuilt by PO. PO also installed a new clutch & pressure plate. It'll still need PB and PS added. Thank's again for the help. Jason __________________ 2007 Chevy 2500HD crew cab, 4x4, duramax w/Allison trans. 2001 Chevy ZR2 Ext. cab 4x4 (DD) 1967 Chevy SWB 4x4, BBC, Th400, NP205, 6" lift, and 35's (In Process) 1970 Chevy Blazer 4x4, BBC, TH400, NP241, 6" lift, and 38.5 boggers in front, 44 boggers on the rear ( mud racer project)

02-23-2005, 09:52 PM	#7
Americanrider Registered User Join Date: Dec 2004 Location: NW, WA. Posts: 1,421	The rocks are a bit noisy at high speed, but just about bomp-proof!

02-25-2005, 01:26 PM	#9
Americanrider Registered User Join Date: Dec 2004 Location: NW, WA. Posts: 1,421	I used plain 'ol 80-90, but once I get the floorpan cleaned from years of neglect I'm going to undercoat the bottom of the cab. Then work on the interior floor, a liner w/ carpet would help mine a great deal. I'm running 4.56's so anything above 50 is Hi-speed for me. Next time I re-lube I'll try something better.



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