12 bolt rear end info ? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

shipma3 · 03-09-2012, 12:32 PM

what gear ratios did they come in for half tons and are the a good axle for offroading? im know my 1978 k10 has a 12 bolt rear and i think its a dana 44 front. are these axles good?

**Zoomad75** · 03-09-2012, 10:26 PM

The 12bolt and D44 are decent axles to start with, provided you don't go too large with the tires and lock them up. 35" is about as large as I'd go. Yes people have gone larger on them, but that doesn't mean they survive for long off road.

There is a pretty good selection of ratios for both. Keep in mind the major downfall to a 12bolt axle is the fact that it's a semi-floating c-clip design. Meaning the only thing that holds the axleshaft in the housing is a c-clip inside the differential. While that seems ok, wait until you bust an axle shaft and what's left is going to start walking it's way out of the housing, wheel, brake drum and all.

If you don't plan on going large or being a uber-rock crawler they will last. I've wheeled for a while on a 12b/d44 combo. I didn't lock it up though on either end with my 35" tires. I'm careful (sometimes) on the throttle and try not to bite off more than my rig can chew (again sometimes!). I'm still planning on upgrading at least to a 14b full floater for added beef/security.

shipma3 · 03-10-2012, 03:16 AM

thanks i plan on 31s so it shoudlnt be a problem then

i belive its already very low gear as it has a heck of a time getting to 60 . which i could care less as it will be an offroader. probably upgrade to a np205 when i can

odog · 03-10-2012, 11:36 AM

like what was already said, the 12 bolt is a c clip axle, so you may carry a couple extra clips in the ash tray and some gear oil when you go wheeling. I had an axle walk out on me in the hills when I was coming home with a load of firewood. It would have been an eay fix if I would have had the clips then, instead it was a long walk.

Mike C · 03-10-2012, 06:49 PM

Seldomly does the clip break. It's the axle itself. The problem with the clip is it is at the very inner part of the axle. So when the axle breaks between the clip and the wheel, the axle slides out of the housing.

03-09-2012, 12:32 PM	#1
shipma3 Registered User Join Date: Mar 2012 Location: manti utah Posts: 67	12 bolt rear end info ? what gear ratios did they come in for half tons and are the a good axle for offroading? im know my 1978 k10 has a 12 bolt rear and i think its a dana 44 front. are these axles good?

03-09-2012, 10:26 PM	#2
Zoomad75 K5Camper Join Date: Mar 2004 Location: Pueblo, CO Posts: 1,513	Re: 12 bolt rear end info ? The 12bolt and D44 are decent axles to start with, provided you don't go too large with the tires and lock them up. 35" is about as large as I'd go. Yes people have gone larger on them, but that doesn't mean they survive for long off road. There is a pretty good selection of ratios for both. Keep in mind the major downfall to a 12bolt axle is the fact that it's a semi-floating c-clip design. Meaning the only thing that holds the axleshaft in the housing is a c-clip inside the differential. While that seems ok, wait until you bust an axle shaft and what's left is going to start walking it's way out of the housing, wheel, brake drum and all. If you don't plan on going large or being a uber-rock crawler they will last. I've wheeled for a while on a 12b/d44 combo. I didn't lock it up though on either end with my 35" tires. I'm careful (sometimes) on the throttle and try not to bite off more than my rig can chew (again sometimes!). I'm still planning on upgrading at least to a 14b full floater for added beef/security. __________________ Rob Z. 1975 K5 350/465/205/D44/12b 4" lift on 35's- RIP 1991 K5 8.1L/NV4500/241/D44/14b FWC Camper

03-10-2012, 03:16 AM	#3
shipma3 Registered User Join Date: Mar 2012 Location: manti utah Posts: 67	Re: 12 bolt rear end info ? thanks i plan on 31s so it shoudlnt be a problem then i belive its already very low gear as it has a heck of a time getting to 60 . which i could care less as it will be an offroader. probably upgrade to a np205 when i can

03-10-2012, 11:36 AM	#4
odog Registered User Join Date: Oct 2007 Location: Wendell, Idaho Posts: 608	Re: 12 bolt rear end info ? like what was already said, the 12 bolt is a c clip axle, so you may carry a couple extra clips in the ash tray and some gear oil when you go wheeling. I had an axle walk out on me in the hills when I was coming home with a load of firewood. It would have been an eay fix if I would have had the clips then, instead it was a long walk. __________________ 1969 4x4 Nothing beats a good rock drill and some dynamite

03-10-2012, 06:49 PM	#5
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,728	Re: 12 bolt rear end info ? Seldomly does the clip break. It's the axle itself. The problem with the clip is it is at the very inner part of the axle. So when the axle breaks between the clip and the wheel, the axle slides out of the housing. __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax



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