Need some rear diff help - The 1947 - Present Chevrolet & GMC Truck Message Board Network

hemihead · 04-05-2009, 02:55 PM

I have two 6 bolt rear diffs.. the funny thing is the axle tube on each diff measure differently and I am wondering if some one shortened 6 bolt axles to fit in a 5 bolt diff.

The axel tube (measured from the center section to the inside of the square mouning flange) on one measures about 20" +/- 1/8" and the other axle measures about 21" or so.

Does any one know what a axle tube on a 5 bolt would be?

I want to switch to 5 bolt axles but was going to purchase the axles and drums from CPP. If I indeed have a 5 bolt diff, I'll go to the wreckers and purchase some used axles.

Longhorn Man · 04-05-2009, 05:25 PM

it sounds like the short one is a mid to late 1970 rear. Gm widened it in mid '70 in preperation for the wider 5 lug rear.

hemihead · 04-05-2009, 09:40 PM

The rear is set up for tariling arms suspension. Did they have this past 1972.

Green Machine · 04-05-2009, 09:52 PM

The wide rear is the one you want to keep if swaping in newer 5 bolt axles from a junkyard. Aftermarket 5 lug axles are available for the shorter rear, but since you have your pick, use the wider one and get the used axles, much cheaper.

Longhorn Man · 04-05-2009, 11:38 PM

72 was the last year for coil springs and trailing arms.

hemihead · 04-06-2009, 10:09 PM

So do you guys think that for the shorter rear end I'll find 5-bolt axles

JimKshortstep4x4 · 04-07-2009, 05:27 AM

5 bolt axles are used in the longer rear end and will be too long for the shorter differential.

Jim

hemihead · 04-07-2009, 11:21 PM

Are you guys saying the longer 6 bolt axles are the same length as the 71/72 5 bolt axles and therefore interchangeable?

Longhorn Man · 04-07-2009, 11:39 PM

exactly

04-05-2009, 02:55 PM	#1
hemihead Registered User Join Date: Mar 2007 Location: Estevan, Sask, Canada Posts: 185	Need some rear diff help I have two 6 bolt rear diffs.. the funny thing is the axle tube on each diff measure differently and I am wondering if some one shortened 6 bolt axles to fit in a 5 bolt diff. The axel tube (measured from the center section to the inside of the square mouning flange) on one measures about 20" +/- 1/8" and the other axle measures about 21" or so. Does any one know what a axle tube on a 5 bolt would be? I want to switch to 5 bolt axles but was going to purchase the axles and drums from CPP. If I indeed have a 5 bolt diff, I'll go to the wreckers and purchase some used axles. __________________ 1967 SWB C-10, BBC 454, T400, 3.73 posi, 20" Coys 1972 K5 Blazer, SBC 400, 4 spd, 3.73, 6" lift, 35" mud grapplers 2011 Sierra Denali HD, 6.6 L Duramax, RBP 96R rims, leveled and Nitto trail grapplers, 2009 Acura MDX

04-05-2009, 05:25 PM	#2
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Re: Need some rear diff help it sounds like the short one is a mid to late 1970 rear. Gm widened it in mid '70 in preperation for the wider 5 lug rear.

04-05-2009, 09:40 PM	#3
hemihead Registered User Join Date: Mar 2007 Location: Estevan, Sask, Canada Posts: 185	Re: Need some rear diff help The rear is set up for tariling arms suspension. Did they have this past 1972. __________________ 1967 SWB C-10, BBC 454, T400, 3.73 posi, 20" Coys 1972 K5 Blazer, SBC 400, 4 spd, 3.73, 6" lift, 35" mud grapplers 2011 Sierra Denali HD, 6.6 L Duramax, RBP 96R rims, leveled and Nitto trail grapplers, 2009 Acura MDX

04-05-2009, 09:52 PM	#4
Green Machine Senior Member Join Date: Jul 2004 Location: Estherville, Iowa Posts: 3,371	Re: Need some rear diff help The wide rear is the one you want to keep if swaping in newer 5 bolt axles from a junkyard. Aftermarket 5 lug axles are available for the shorter rear, but since you have your pick, use the wider one and get the used axles, much cheaper. __________________ 1968 C10 307 3spd Long Fleet ------ http://67-72chevytrucks.com/vboard/s...d.php?t=201103 1970 C10 305 Super T10 Long Fleet --- http://67-72chevytrucks.com/vboard/s...d.php?t=202285 1971 C20 383 TH350 Dana Posi ----- http://67-72chevytrucks.com/vboard/s...d.php?t=206894 2001 GMC Sierra 1500 C3 6.0

04-05-2009, 11:38 PM	#5
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Re: Need some rear diff help 72 was the last year for coil springs and trailing arms.

04-06-2009, 10:09 PM	#6
hemihead Registered User Join Date: Mar 2007 Location: Estevan, Sask, Canada Posts: 185	Re: Need some rear diff help So do you guys think that for the shorter rear end I'll find 5-bolt axles __________________ 1967 SWB C-10, BBC 454, T400, 3.73 posi, 20" Coys 1972 K5 Blazer, SBC 400, 4 spd, 3.73, 6" lift, 35" mud grapplers 2011 Sierra Denali HD, 6.6 L Duramax, RBP 96R rims, leveled and Nitto trail grapplers, 2009 Acura MDX

04-07-2009, 05:27 AM	#7
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Re: Need some rear diff help 5 bolt axles are used in the longer rear end and will be too long for the shorter differential. Jim __________________ 1971 Shortbox step side 4x4, 350 sbc, 3:07 rear end 1965 Impala SS 400 sbc, Muncie rock crusher 1966 Impala SS 396 bbc, TH 400 1969 El Camino, 350 sbc, TH 350 1971 Snowplow built on a Blazer frame 1972 GMC Short bed, stepside, TH 400, 427 BBC

04-07-2009, 11:21 PM	#8
hemihead Registered User Join Date: Mar 2007 Location: Estevan, Sask, Canada Posts: 185	Re: Need some rear diff help Are you guys saying the longer 6 bolt axles are the same length as the 71/72 5 bolt axles and therefore interchangeable? __________________ 1967 SWB C-10, BBC 454, T400, 3.73 posi, 20" Coys 1972 K5 Blazer, SBC 400, 4 spd, 3.73, 6" lift, 35" mud grapplers 2011 Sierra Denali HD, 6.6 L Duramax, RBP 96R rims, leveled and Nitto trail grapplers, 2009 Acura MDX Last edited by hemihead; 04-07-2009 at 11:22 PM.

04-07-2009, 11:39 PM	#9
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Re: Need some rear diff help exactly



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