64 C10 12 Bolt Rear Axle - The 1947 - Present Chevrolet & GMC Truck Message Board Network

gsharp · 04-08-2021, 05:02 PM

Couple things, I want to convert the rear axle on my 64 to 5 lug and put a 3.08:1 ring and pinion in. Question is the 64 12 bolt not the same as the up to 72 rear ends? What size carrier is in my 64 12 bolt with the factory 3.73:1 gears?

gmc684x4 · 04-08-2021, 05:07 PM

The carrier will be the same
The axles are the same up to early 70
Late 70 to about 81 the 12 bolt is slightly wider taking a different axle set
Summit Moser and many others have 5 bolt axles for the pre 70 12 bolt

**cwcarpenter98** · 04-08-2021, 09:11 PM

The 63-64 12 bolts used 17 spline axles and spider gears. I've read that the axle bearing is different as well, but can't confirm myself as the previous owner swapped in a 65-70 12 bolt a long time ago

**The Rocknrod** · 04-08-2021, 09:50 PM

I bought an entire kit hub to hub from Quick for my 64 12 bolt. Moser 31 spline, Detroit gears, Eaton posi, bearings seals etc.
However the seals were different than what came with the kit, the ones I needed were National Oil Seals 8871.

gmc684x4 · 04-09-2021, 02:02 AM

I thought they where all the same spline
all my diffs are 67 to 77 I have in my collection
early 12 bolt truck axles are 30 3/4 " long
late 70 up are 31 7/16 " long

you can contact Usa standard Gear ask about the axle bearings difference use a newer 30 spline carrier posi or open in a 3 series

or look for a newer diff with 3.08 in it already

this is the 5 bolt swap axles from rock auto for a 67 diff

https://www.rockauto.com/en/moreinfo...321108&jsn=984

04-08-2021, 05:02 PM	#1
gsharp Registered User Join Date: Jul 2017 Location: Milan, Ohio Posts: 31	64 C10 12 Bolt Rear Axle Couple things, I want to convert the rear axle on my 64 to 5 lug and put a 3.08:1 ring and pinion in. Question is the 64 12 bolt not the same as the up to 72 rear ends? What size carrier is in my 64 12 bolt with the factory 3.73:1 gears?

04-08-2021, 05:07 PM	#2
gmc684x4 Registered User Join Date: Jul 2012 Location: Whitehorse yukon Posts: 1,218	Re: 64 C10 12 Bolt Rear Axle The carrier will be the same The axles are the same up to early 70 Late 70 to about 81 the 12 bolt is slightly wider taking a different axle set Summit Moser and many others have 5 bolt axles for the pre 70 12 bolt

04-08-2021, 09:11 PM	#3
cwcarpenter98 Senior Member Join Date: Jan 2018 Location: Hickory Flat, GA Posts: 4,488	Re: 64 C10 12 Bolt Rear Axle The 63-64 12 bolts used 17 spline axles and spider gears. I've read that the axle bearing is different as well, but can't confirm myself as the previous owner swapped in a 65-70 12 bolt a long time ago __________________ Christian Carpenter 1963 C10 - Frankentruck 283, Muncie 3 speed with overdrive Overdrive wiring here 1963-ish truck bed trailer - Half-Wit 1981 C10 - Penny 305, th350 --> Soon to be 350, Saginaw 4 speed 1995 Dodge Dakota Sport "I'll put it simple: if you're going hard enough left, you'll find yourself turning right." - Doc Hudson

04-08-2021, 09:50 PM	#4
The Rocknrod Moderator Join Date: Aug 2011 Location: China Spring, TX Posts: 7,280	Re: 64 C10 12 Bolt Rear Axle I bought an entire kit hub to hub from Quick for my 64 12 bolt. Moser 31 spline, Detroit gears, Eaton posi, bearings seals etc. However the seals were different than what came with the kit, the ones I needed were National Oil Seals 8871. __________________ Master Chief, US Navy, Retired 1964 C10 Step-side Short Bed - In Progress 2009 2500HD Duramax LTZ 1948 GMC Panel 1956 Big Window Stepside 1953 5 Window Chevy Stepside 1932 Coupe New Seat Foam for Bench Seats? Last edited by The Rocknrod; 04-09-2021 at 07:48 AM.

04-09-2021, 02:02 AM	#5
gmc684x4 Registered User Join Date: Jul 2012 Location: Whitehorse yukon Posts: 1,218	Re: 64 C10 12 Bolt Rear Axle I thought they where all the same spline all my diffs are 67 to 77 I have in my collection early 12 bolt truck axles are 30 3/4 " long late 70 up are 31 7/16 " long you can contact Usa standard Gear ask about the axle bearings difference use a newer 30 spline carrier posi or open in a 3 series or look for a newer diff with 3.08 in it already this is the 5 bolt swap axles from rock auto for a 67 diff https://www.rockauto.com/en/moreinfo...321108&jsn=984



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