Rear Axle Swap??? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Blue85 · 02-21-2006, 03:11 PM

I got a rear axle from a 99 chev 1/2 ton sitting in my pile of junk with a 3.73 posi inside of it, I would like to swap it into my 72, any ever do this swap? I know i will have to change spring pads and mabye shock mounts. The rear disc brakes would be sweet to have.

**dennislbrooks** · 02-21-2006, 03:36 PM

I know if I had it, I would try it. My wife has to keep an eye on me measuring things on her Yukon. Will you have to adapt for metric brake lines? And do you see any prob on the ebrake? And how about the driveshaft coupling?

Blue85 · 02-21-2006, 03:49 PM

I still gotta go to farm and dig the axle oout of the snow bank and check things out, also have to try and remmber where i saw mounting pads, I think it was ina Chevy Duty Cataloge.

70rs/ss · 02-21-2006, 03:52 PM

Here is the kicker, the newer model stuff has the pumkin (center section) offset to clear the fuel tank. One axle tube is longer than the other, so if you line it up to put the tires in the wheel wells the center will be more to the passengers side and therefor put the driveshaft at an odd angle. I did the opposite put a 68 rear in a 97 truck, I just lined up the wheels in the wells, then moved it half the distance to the passengers side to give tank clearance and to lessen the angle. Overa;; the difference from side to side was not visable to the casual observer and the ride was good with no pulling on a launch, but I was concerned about the drive line and have since scrapped the whole project. It can work just know what you are getting into with the unequal axle lengths and potential driveline snafus.

**dennislbrooks** · 02-21-2006, 03:53 PM

Not sure but pads probably could be made out of 2 or 3 inch 1/4" channel. Dig out of snowbank--and we complain here of 40 degree weather in Dallas.

Blue85 · 02-21-2006, 03:58 PM

Dennis Do you have the axle width measurements?, how about axle tube diameter?

**dennislbrooks** · 02-21-2006, 05:59 PM

I do not have the measurements right off hand---may slip outside if it stops raining and measure the yukon. I believe it is a bit wider which could be a good thing with most of the newer wheels having a lot of backspacing.

Your 98 should be near the same even if rear drum.

OK-this is approx on a 2004 Yukon with rear disc --- from outside axle flange
where wheel rest ----- about 65-66". Take some careful measurements when you dig it out of snow drift. If the axle is within 200 foot of house --getting it may be your wife's resposiblity. 8-)

Axle housing diameter measures very close to 3" if not 3". Her axle is very similar to my 2002 Z71 with rear disc.

Others may know.

Blue85 · 02-21-2006, 06:16 PM

Thanks alot man

02-21-2006, 03:11 PM	#1
Blue85 Oilfield Trash Join Date: Sep 2003 Location: Raymore, Sk, Canada, Earth Posts: 3,170	Rear Axle Swap??? I got a rear axle from a 99 chev 1/2 ton sitting in my pile of junk with a 3.73 posi inside of it, I would like to swap it into my 72, any ever do this swap? I know i will have to change spring pads and mabye shock mounts. The rear disc brakes would be sweet to have. __________________ 14 Dodge 3500 Mega Cab 08 Dodge 3500 Mega Cab 87 Chev 3+3 4x4 80 GMC K10 High Sierra bone stock 70 Chevelle 350SS long term project 68 GMC 3ton Grain Truck/Garbage wagon 50 Pontiac 2 Door Coupe Project "I've got a shotgun rifle and a 4 wheel drive and a country boy can survive" Hank Jr.

02-21-2006, 03:36 PM	#2
dennislbrooks Senior Member Join Date: Feb 2004 Location: Williamsburg, Ohio Posts: 1,798	Re: Rear Axle Swap??? I know if I had it, I would try it. My wife has to keep an eye on me measuring things on her Yukon. Will you have to adapt for metric brake lines? And do you see any prob on the ebrake? And how about the driveshaft coupling?

02-21-2006, 03:49 PM	#3
Blue85 Oilfield Trash Join Date: Sep 2003 Location: Raymore, Sk, Canada, Earth Posts: 3,170	Re: Rear Axle Swap??? I still gotta go to farm and dig the axle oout of the snow bank and check things out, also have to try and remmber where i saw mounting pads, I think it was ina Chevy Duty Cataloge. __________________ 14 Dodge 3500 Mega Cab 08 Dodge 3500 Mega Cab 87 Chev 3+3 4x4 80 GMC K10 High Sierra bone stock 70 Chevelle 350SS long term project 68 GMC 3ton Grain Truck/Garbage wagon 50 Pontiac 2 Door Coupe Project "I've got a shotgun rifle and a 4 wheel drive and a country boy can survive" Hank Jr.

02-21-2006, 03:52 PM	#4
70rs/ss Registered User Join Date: Dec 2004 Location: Northern AZ Posts: 7,270	Re: Rear Axle Swap??? Here is the kicker, the newer model stuff has the pumkin (center section) offset to clear the fuel tank. One axle tube is longer than the other, so if you line it up to put the tires in the wheel wells the center will be more to the passengers side and therefor put the driveshaft at an odd angle. I did the opposite put a 68 rear in a 97 truck, I just lined up the wheels in the wells, then moved it half the distance to the passengers side to give tank clearance and to lessen the angle. Overa;; the difference from side to side was not visable to the casual observer and the ride was good with no pulling on a launch, but I was concerned about the drive line and have since scrapped the whole project. It can work just know what you are getting into with the unequal axle lengths and potential driveline snafus.

02-21-2006, 03:53 PM	#5
dennislbrooks Senior Member Join Date: Feb 2004 Location: Williamsburg, Ohio Posts: 1,798	Re: Rear Axle Swap??? Not sure but pads probably could be made out of 2 or 3 inch 1/4" channel. Dig out of snowbank--and we complain here of 40 degree weather in Dallas.

02-21-2006, 03:58 PM	#6
Blue85 Oilfield Trash Join Date: Sep 2003 Location: Raymore, Sk, Canada, Earth Posts: 3,170	Re: Rear Axle Swap??? Dennis Do you have the axle width measurements?, how about axle tube diameter? __________________ 14 Dodge 3500 Mega Cab 08 Dodge 3500 Mega Cab 87 Chev 3+3 4x4 80 GMC K10 High Sierra bone stock 70 Chevelle 350SS long term project 68 GMC 3ton Grain Truck/Garbage wagon 50 Pontiac 2 Door Coupe Project "I've got a shotgun rifle and a 4 wheel drive and a country boy can survive" Hank Jr.

02-21-2006, 05:59 PM	#7
dennislbrooks Senior Member Join Date: Feb 2004 Location: Williamsburg, Ohio Posts: 1,798	Re: Rear Axle Swap??? I do not have the measurements right off hand---may slip outside if it stops raining and measure the yukon. I believe it is a bit wider which could be a good thing with most of the newer wheels having a lot of backspacing. Your 98 should be near the same even if rear drum. OK-this is approx on a 2004 Yukon with rear disc --- from outside axle flange where wheel rest ----- about 65-66". Take some careful measurements when you dig it out of snow drift. If the axle is within 200 foot of house --getting it may be your wife's resposiblity. 8-) Axle housing diameter measures very close to 3" if not 3". Her axle is very similar to my 2002 Z71 with rear disc. Others may know. Last edited by dennislbrooks; 02-21-2006 at 06:00 PM.

02-21-2006, 06:16 PM	#8
Blue85 Oilfield Trash Join Date: Sep 2003 Location: Raymore, Sk, Canada, Earth Posts: 3,170	Re: Rear Axle Swap??? Thanks alot man __________________ 14 Dodge 3500 Mega Cab 08 Dodge 3500 Mega Cab 87 Chev 3+3 4x4 80 GMC K10 High Sierra bone stock 70 Chevelle 350SS long term project 68 GMC 3ton Grain Truck/Garbage wagon 50 Pontiac 2 Door Coupe Project "I've got a shotgun rifle and a 4 wheel drive and a country boy can survive" Hank Jr.



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