HELP!North TX '69 GMC rear axle swap clarification - The 1947 - Present Chevrolet & GMC Truck Message Board Network

tx69gmc · 04-29-2006, 09:00 PM

Hi guys-

Can someone please clarify once and for all for me which donor rear ends I can use to swap into my 69 GMC SWB to get a 5 lug rear? Are they any that will work that are available with Posi? I am really wanting to do this swap but get quite a few different opinions out there I think that finding a donor truck would be the easiest and most economical. Correct me if I am wrong. Many thanks.............. Anybody in the North Texas area that has done this swap please speak up.

matt67350 · 04-29-2006, 09:19 PM

You can redrill your current axles, and change to 5 lug drums.
Is your setup coil or leaf?

tx69gmc · 04-29-2006, 09:28 PM

I have been speaking with Dennis Brooks about redrilling the axles. This seems a bit dangerous(no offense Dennis) but that may not be the case. I would love to hear from some that have done this. I am set up with leaf.

jsbgump · 04-29-2006, 10:09 PM

If it is a leaf spring set up go to your local junk yard and find one with the gears you want and slide it in and bolt it up.

TugOwar · 04-29-2006, 10:16 PM

Quote:

Originally Posted by jsbgump

If it is a leaf spring set up go to your local junk yard and find one with the gears you want and slide it in and bolt it up.

Is there not a difference of width to be concerned with?

farmtruckIII · 04-30-2006, 12:44 AM

Ok here it is, if the truck is leaf sprung any rear end up to 87 will work, exept for one minor detail. The right rear shock mount has to be flipped from one side of the axle tube to the other, because 73-87 had staggard shocks. You can also just replace the axles all 12 bolt trucks use 28 spline axles. If it is coil sprung the axle swap is the easy way out, unless your good at fabrication work. I have done several of these swaps, my 70 step side has the original housing and 78 axles, my friends 72 GMC has a 2.73 one legger out of an 87, and my 71 gmc has a 3.42 posi out of a 72 van. If you need help with the swap I am more than willing to lend a hand.

tx69gmc · 04-30-2006, 06:18 PM

Ttt

jsbgump · 04-30-2006, 06:45 PM

Not with a leaf spring set up

Quote:

Originally Posted by TugOwar

Is there not a difference of width to be concerned with?

TugOwar · 04-30-2006, 09:21 PM

Quote:

Originally Posted by jsbgump

Not with a leaf spring set up

Excellent, thanks for clarifying that.

gringoloco · 05-03-2006, 09:33 PM

OK- So if I have a late(73-87) rear, I can swap the guts into a wide(71-72) coil rear housing?

No spacers or other shenanigans required?

Anyone have mounting flange-to-mounting flange measurements on these?

wibilly · 05-03-2006, 10:56 PM

farmtruckIII so the spring perches are in the same location? i was under the impression they had to be relocated as well

farmtruckIII · 05-04-2006, 03:42 AM

The spring perches are in the same locality, the shock mount on the passenger side must be moved, every thing else works. Yes gringo loco the guts will swap, done it several times.

fade94 · 05-04-2006, 08:34 AM

TX69GMC - I sent you a PM.

gringoloco · 05-04-2006, 10:34 AM

Anyone have width mearurements on early(67-70) and late(71-72) rears? I understand there is a difference of an 1 1/2". Search netted nada for me...

-Chris

cell · 05-09-2006, 06:48 PM

Quote:

If it is coil sprung the axle swap is the easy way out, unless your good at fabrication work.

Whoa! somehow I missed this originally. So, if I have a 67 coil sprung rear, and want a 3.08 rear with disc brake axles, I might be able to just grab the guts from a 73+ rear? Or were all of the 73-87 rears drum brakes?

jsbgump · 05-09-2006, 06:52 PM

They were all drum. I think it was the 78 caddy seveille that has the disk brake 5 on 5 set up

wibilly · 05-09-2006, 10:28 PM

76-78 eldorado's had rear discs with 5 on 5 pattern

**crossy** · 08-24-2007, 04:18 PM

I want to bring this thread back to life. found it in a search.
SO are there measurements to PROPERLY identify my 5 lug rear diff. it is Coil sp rung and in a 69 but again it is 5 lug and i'm guessing it is from a 71-72 then.
If i wanted to make it 6lug i CANNOT???? use just any year of the 67-72's , but could easily use the 73-87 4x4 6 lug axles????

yes, this is a reversal of what most want to do, but there is a method to my madness.
At least that's what i tell my shrink:-)

krue · 08-24-2007, 05:15 PM

You could find the axles out of a late 70 rear end and get 6 lug also. (I'm doing the opposite, I'm gonna take 5 lug axles out of my 72 parts truck and put in place of the 6 lug axles in my 70).

Painter D · 08-24-2007, 06:21 PM

just shell out 1200$ and have a rearend built bad a$ thats what i did

04-29-2006, 09:00 PM	#1
tx69gmc Registered User Join Date: Nov 2005 Location: Denton,TX Posts: 61	HELP!North TX '69 GMC rear axle swap clarification Hi guys- Can someone please clarify once and for all for me which donor rear ends I can use to swap into my 69 GMC SWB to get a 5 lug rear? Are they any that will work that are available with Posi? I am really wanting to do this swap but get quite a few different opinions out there I think that finding a donor truck would be the easiest and most economical. Correct me if I am wrong. Many thanks.............. Anybody in the North Texas area that has done this swap please speak up.

04-29-2006, 09:19 PM	#2
matt67350 Registered User Join Date: May 2001 Location: Benbrook, TX Posts: 1,060	Re: HELP!North TX '69 GMC rear axle swap clarification You can redrill your current axles, and change to 5 lug drums. Is your setup coil or leaf? __________________ 69 swb stepside, rebuild and upgrade in progress Last edited by matt67350; 04-29-2006 at 09:21 PM.

04-29-2006, 09:28 PM	#3
tx69gmc Registered User Join Date: Nov 2005 Location: Denton,TX Posts: 61	Re: HELP!North TX '69 GMC rear axle swap clarification I have been speaking with Dennis Brooks about redrilling the axles. This seems a bit dangerous(no offense Dennis) but that may not be the case. I would love to hear from some that have done this. I am set up with leaf.

04-29-2006, 10:09 PM	#4
jsbgump Gone Fishing Join Date: Aug 2005 Location: Fort Worth, Texas 76135 Posts: 12,361	Re: HELP!North TX '69 GMC rear axle swap clarification If it is a leaf spring set up go to your local junk yard and find one with the gears you want and slide it in and bolt it up. __________________ 68 Chevy Short Fleetside LSX Swap Under Way 3.73 posi 2.5/4 drop Frame of resto has been started 2022 Hyundai Tucson Limited 2019 Chevy Traverse Redline Edition Wifes Ride Build Thread http://67-72chevytrucks.com/vboard/s...=1#post3483616

04-30-2006, 12:44 AM	#6
farmtruckIII 71 GMC 454/TH400 Join Date: Dec 2005 Location: Blue Mound TX Posts: 214	Re: HELP!North TX '69 GMC rear axle swap clarification Ok here it is, if the truck is leaf sprung any rear end up to 87 will work, exept for one minor detail. The right rear shock mount has to be flipped from one side of the axle tube to the other, because 73-87 had staggard shocks. You can also just replace the axles all 12 bolt trucks use 28 spline axles. If it is coil sprung the axle swap is the easy way out, unless your good at fabrication work. I have done several of these swaps, my 70 step side has the original housing and 78 axles, my friends 72 GMC has a 2.73 one legger out of an 87, and my 71 gmc has a 3.42 posi out of a 72 van. If you need help with the swap I am more than willing to lend a hand. __________________ "The bigger you are the harder you fall, the farther you walk the longer you crawl."

04-30-2006, 06:18 PM	#7
tx69gmc Registered User Join Date: Nov 2005 Location: Denton,TX Posts: 61	Re: HELP!North TX '69 GMC rear axle swap clarification Ttt

05-03-2006, 09:33 PM	#10
gringoloco A guy with a truck Join Date: Sep 2005 Location: Germany, for now Posts: 5,920	Re: HELP!North TX '69 GMC rear axle swap clarification OK- So if I have a late(73-87) rear, I can swap the guts into a wide(71-72) coil rear housing? No spacers or other shenanigans required? Anyone have mounting flange-to-mounting flange measurements on these? __________________ -Chris Instagram _elgringoloco_ '70 Short-Wide How to: Ruin a perfectly good C10 ‘70 Blazer ConversionHow To: Ruin a Perfectly Good 4wd '72 Highlander How To: Ruin a Perfectly Good K/5 (SOLD) '72 Blazer 2WD How to: Ruin a perfectly good Blazer (SOLD) '05 Yukon Daily Driven (not so stock) Yukon (SOLD) ‘07 Yukon Denali (daily) Members met list: SCOTI, darkhorse970, 67cheby, 67cheby'sGirl, klmore, porterbuilt, n2billet, Fastrucken, classicchev, Col Clank, GSFMECH, HuggerCST, Spray-Bomb, BACKYARD88, 5150, fine69, fatbass, smbrouss70, 65StreetCruiser, GAc10boy

05-03-2006, 10:56 PM	#11
wibilly Senior Member Join Date: Nov 2005 Location: northwestern wi Posts: 2,111	Re: HELP!North TX '69 GMC rear axle swap clarification farmtruckIII so the spring perches are in the same location? i was under the impression they had to be relocated as well __________________ common sense isn't so common anymore

05-04-2006, 03:42 AM	#12
farmtruckIII 71 GMC 454/TH400 Join Date: Dec 2005 Location: Blue Mound TX Posts: 214	Re: HELP!North TX '69 GMC rear axle swap clarification The spring perches are in the same locality, the shock mount on the passenger side must be moved, every thing else works. Yes gringo loco the guts will swap, done it several times. __________________ "The bigger you are the harder you fall, the farther you walk the longer you crawl."

05-04-2006, 08:34 AM	#13
fade94 Registered User Join Date: Mar 2005 Location: Melissa, TX Posts: 799	Re: HELP!North TX '69 GMC rear axle swap clarification TX69GMC - I sent you a PM. __________________ 68 short bed driver (71 clip on it now, swapping to 68 when weather cooperates) 67 short step project (will get SWB from the 68) 67 Camaro, #'s matching (my wife's) 03 Dodge Ram 2500 4x4 diesel 5 speed 4.10 rear Last edited by fade94; 05-04-2006 at 08:36 AM.

05-04-2006, 10:34 AM	#14
gringoloco A guy with a truck Join Date: Sep 2005 Location: Germany, for now Posts: 5,920	Re: HELP!North TX '69 GMC rear axle swap clarification Anyone have width mearurements on early(67-70) and late(71-72) rears? I understand there is a difference of an 1 1/2". Search netted nada for me... -Chris __________________ -Chris Instagram _elgringoloco_ '70 Short-Wide How to: Ruin a perfectly good C10 ‘70 Blazer ConversionHow To: Ruin a Perfectly Good 4wd '72 Highlander How To: Ruin a Perfectly Good K/5 (SOLD) '72 Blazer 2WD How to: Ruin a perfectly good Blazer (SOLD) '05 Yukon Daily Driven (not so stock) Yukon (SOLD) ‘07 Yukon Denali (daily) Members met list: SCOTI, darkhorse970, 67cheby, 67cheby'sGirl, klmore, porterbuilt, n2billet, Fastrucken, classicchev, Col Clank, GSFMECH, HuggerCST, Spray-Bomb, BACKYARD88, 5150, fine69, fatbass, smbrouss70, 65StreetCruiser, GAc10boy

05-09-2006, 06:52 PM	#16
jsbgump Gone Fishing Join Date: Aug 2005 Location: Fort Worth, Texas 76135 Posts: 12,361	Re: HELP!North TX '69 GMC rear axle swap clarification They were all drum. I think it was the 78 caddy seveille that has the disk brake 5 on 5 set up __________________ 68 Chevy Short Fleetside LSX Swap Under Way 3.73 posi 2.5/4 drop Frame of resto has been started 2022 Hyundai Tucson Limited 2019 Chevy Traverse Redline Edition Wifes Ride Build Thread http://67-72chevytrucks.com/vboard/s...=1#post3483616

05-09-2006, 10:28 PM	#17
wibilly Senior Member Join Date: Nov 2005 Location: northwestern wi Posts: 2,111	Re: HELP!North TX '69 GMC rear axle swap clarification 76-78 eldorado's had rear discs with 5 on 5 pattern __________________ common sense isn't so common anymore

08-24-2007, 04:18 PM	#18
crossy Oh,you can't buy that new Join Date: Apr 2000 Location: Pennsville,N.J. 08070, USA Posts: 2,039	Re: HELP!North TX '69 GMC rear axle swap clarification I want to bring this thread back to life. found it in a search. SO are there measurements to PROPERLY identify my 5 lug rear diff. it is Coil sp rung and in a 69 but again it is 5 lug and i'm guessing it is from a 71-72 then. If i wanted to make it 6lug i CANNOT???? use just any year of the 67-72's , but could easily use the 73-87 4x4 6 lug axles???? yes, this is a reversal of what most want to do, but there is a method to my madness. At least that's what i tell my shrink:-) __________________ "been there, done that, ruined the T-shirt". 2007 LBZ GMC Sierra, ECSB 2006 LM7 RCSB Silverado 98 Vortec project. 94,3500,6.5L 4L80 81 SWB GMC POS finally gone 73 Pinto, stock, w/CragarSS's-eww LOTS of Cummins trucks.

08-24-2007, 05:15 PM	#19
krue Designated A-hole! Join Date: Mar 2003 Location: South Mississippi Posts: 36,450	Re: HELP!North TX '69 GMC rear axle swap clarification You could find the axles out of a late 70 rear end and get 6 lug also. (I'm doing the opposite, I'm gonna take 5 lug axles out of my 72 parts truck and put in place of the 6 lug axles in my 70). __________________ "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"



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08-24-2007, 06:21 PM	#20
Painter D Registered User Join Date: Jun 2007 Location: DFW (Forney) Posts: 1,529	Re: HELP!North TX '69 GMC rear axle swap clarification just shell out 1200$ and have a rearend built bad a$ thats what i did

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