4x fng, so how do I tell? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

krue · 02-26-2005, 12:05 AM

I just drug a 72 blazer home and was wondering how to tell what transfer case and front end it's got under it. It's a 6cyl with what I think is a 3 speed tranny.

How hard will it be to put a 4 speed in this thing and which would be the best and/or easiest to swap in. No major mudding and their ain't no rocks in South Mississippi!

Prerunner1982 · 02-26-2005, 12:19 AM

probably has a dana 44 under the front, as far as t case.. is it divorced or attached to the trans? if its divorced it is probably a rockwell 221, but i dont know when they stopped doing that.. sorry not much help, sure the experts will come along and proved me wrong..

*1FaastC10* · 02-26-2005, 12:35 AM

definitely a D44/12 bolt. should be a closed knuckle D44, which IIRC is a little weaker than an open knuckle 44 or 10 bolt

72 CustomCamper · 02-26-2005, 01:02 AM

With a 3 spd it's more than likely a Dana 20 Tcase...

Chuck

Rod · 02-26-2005, 01:30 AM

If its a 72 will be an open knuckle 44 disc brake front and a dana 20 transfer case most likely...if no shift pattern on the knob and a shift pattern on the floor shifter boot retaining ring...and the shifter for transfer case moves to the left also to engage an axle..its a dana 20.

Could have a NP 205..but rarer with a 3 spd.

If it has the np 205..that easier to find the parts for to make it a 4spd. You'd need tranfer case adapter and a tranny to start.

1969 GMC · 02-26-2005, 03:37 AM

T221 was never offered in K5's and '69 was the only year they had closed knuckles. I bet its the 3 spd/Dana 20.

**Yukon Jack** · 02-26-2005, 10:18 AM

It won't be difficult to put a 4 speed in your truck but if you have a Dana 20 I would look for a 4 speed/NP205 combo to replace it with. Much easier to find that combo than an adapter to mate the 4 speed to a Dana 20.

You will need either a NP205 crossmember or drop the Dana 20 crossmember about 3/4" to 1". I beleive your driveshaft lengths will not need to modified.

Pretty straight forward swap.

02-26-2005, 12:05 AM	#1
krue Designated A-hole! Join Date: Mar 2003 Location: South Mississippi Posts: 36,448	4x fng, so how do I tell? I just drug a 72 blazer home and was wondering how to tell what transfer case and front end it's got under it. It's a 6cyl with what I think is a 3 speed tranny. How hard will it be to put a 4 speed in this thing and which would be the best and/or easiest to swap in. No major mudding and their ain't no rocks in South Mississippi! __________________ "If it ain't broke, fix it 'til it is!" Being stupid ain't illegal. We're Still Debt Free Except for the House!!! www.daveramsey.com 70 GMC SWB Stepside project "Green Booger" soon to be 6.0l/4l80e 93 S-10 "Poppaw's Truck"

02-26-2005, 12:19 AM	#2
Prerunner1982 Registered User Join Date: Oct 2002 Location: Edmond, OK Posts: 5,904	probably has a dana 44 under the front, as far as t case.. is it divorced or attached to the trans? if its divorced it is probably a rockwell 221, but i dont know when they stopped doing that.. sorry not much help, sure the experts will come along and proved me wrong.. __________________ Jon 1982 Chevy Silverado 350/th350.... RETIRED 1993 Jeep XJ 2 door(Cherokee) 4wd 4.0ltr/AX-15 (5spd)/NP231 .... Oklahoma Roll Call

02-26-2005, 01:02 AM	#4
72 CustomCamper huh ??? Join Date: Nov 2002 Location: Fredericksburg,Va. Posts: 3,368	With a 3 spd it's more than likely a Dana 20 Tcase... Chuck __________________ 90 Blazer Silverado 350w/ 700R4 and 32" Kelly's "I am a bomb technician. If you see me running try to keep up!"

02-26-2005, 01:30 AM	#5
Rod Join Date: Dec 1999 Location: Eastern - Manitoba Canada, Winnipeg Posts: 4,369	If its a 72 will be an open knuckle 44 disc brake front and a dana 20 transfer case most likely...if no shift pattern on the knob and a shift pattern on the floor shifter boot retaining ring...and the shifter for transfer case moves to the left also to engage an axle..its a dana 20. Could have a NP 205..but rarer with a 3 spd. If it has the np 205..that easier to find the parts for to make it a 4spd. You'd need tranfer case adapter and a tranny to start. __________________ Senior active founding member. 70 3/4 ton GMC Suburban 4x4 250/4 spd. 71 1/2 ton Suburban Chevy 4x4, 350/350 72 Chev 1 ton tow truck 402BB w/Holmes 440 wrecker on propane 2005 FLSTSCI Harley Springer 85 FXSB Harley Lowrider 72 Triumph 650 Bonneville 5spd "Poor people don't have hobbies" Quote from wife.

02-26-2005, 03:37 AM	#6
1969 GMC Registered User Join Date: Feb 2003 Location: The Rubber City Posts: 5,498	T221 was never offered in K5's and '69 was the only year they had closed knuckles. I bet its the 3 spd/Dana 20. __________________ 1969 GMC K2500 1996 Honda Accord 2007 Kawasaki KLR 650

02-26-2005, 12:35 AM	#3
1FaastC10 Account Suspended Join Date: Oct 2002 Location: Elkhart, IN Posts: 6,399	definitely a D44/12 bolt. should be a closed knuckle D44, which IIRC is a little weaker than an open knuckle 44 or 10 bolt

02-26-2005, 10:18 AM	#7
Yukon Jack Post Whore Join Date: Feb 2000 Location: Rose Hill, KS, USA Posts: 12,686	It won't be difficult to put a 4 speed in your truck but if you have a Dana 20 I would look for a 4 speed/NP205 combo to replace it with. Much easier to find that combo than an adapter to mate the 4 speed to a Dana 20. You will need either a NP205 crossmember or drop the Dana 20 crossmember about 3/4" to 1". I beleive your driveshaft lengths will not need to modified. Pretty straight forward swap. __________________ 1970 Blazer with a 400 sbc and 4" lift 1980 Pontiac Trans Am, 455 Oldsmobile 2012 Kawasaki Concours 14

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