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73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: muddjar on May 10, 2012, 12:56:30 pm

Title: Need help
Post by: muddjar on May 10, 2012, 12:56:30 pm
This is my 81 short wide I am in search of a new rearend and was wandering if I could upgrade to a newer style if any would fit. Its a 10 bolt I looked in rearend and the only staped numbers I seen were 89 b and 8370 so how to tell what gears I have thanks
Title: Re: Need help
Post by: DustyRusty on May 10, 2012, 05:00:47 pm
What's wrong with the 10-bolt?  Is it broken?  These aren't bad axles.  However a 12-bolt from this era of truck shoult be a direct swap and will provide a little extra strength.

Since you already have the diff cover off you can determine the ratio by dividing the number of teeth on the pinion into the number of  teeth on the ring gear.  Ex.:  Say there are 10 teeth on the pinion and 41 on the ring gear, you would have a 4.10:1 ratio, etc.  Sometimes the ratio is stamped on the ring gear itself but based on your post it appears that it wasn't.
Title: Re: Need help
Post by: muddjar on May 10, 2012, 09:33:11 pm
Thanks dusty I Jacked her up and rotated the wheel and she has 273. So I went to a junkyard today and found a 12 bolt but it is in a diesel truck so does that matter just wandering
Title: Re: Need help
Post by: Blazin on May 10, 2012, 11:28:08 pm
Motor doesn't matter as far as rear axle goes. Pull the cover off and check the ratio the way Dusty said. Or if it has numbers stamped in the edge of the ring gear its usually the last two numbers separated by a : divide the smaller number into the larger one.
You will need a cross over U joint. one side fits your drive shaft, the other fits the 12 bolt yoke. 12 bolts uses a little bit shorter cross, and smaller caps than a 10 bolt.

What is wrong with your current rear axle?
Title: Re: Need help
Post by: muddjar on May 10, 2012, 11:50:26 pm
It has a lot of slack. U no I 'spin the wheel and it takes awhile to start to move and the person I bought it from ran it with out fluid
Title: Re: Need help
Post by: Blazin on May 11, 2012, 06:13:49 am
? U no? U joint?
Title: Re: Need help
Post by: gto109 on May 11, 2012, 12:03:16 pm
I think he ment "you know"
Title: Re: Need help
Post by: muddjar on May 11, 2012, 04:54:32 pm
Just wandering if I could use the chunk out of a 4 wheel drive in mine I was told as long as it is a 10 bolt. Is that right please help
Title: Re: Need help
Post by: Blazin on May 12, 2012, 12:47:29 am
4 wheel drive axle is the same. Just need to swap your backing plates, and brakes onto it. Slide you axles in, put your drums, and wheels on.
Title: Re: Need help
Post by: bake74 on May 12, 2012, 10:17:14 am
     Or see how much a local shop can fix yours for if you can not, or do not want to fix it.
Title: Re: Need help
Post by: muddjar on May 13, 2012, 12:45:29 am
Someone said that my rearend was a 28 spline but I can't find a 28 spline for a Chevy so what do I do. How can I order the ring & pinion if it don't show that they have it
Title: Re: Need help
Post by: VileZambonie on May 13, 2012, 07:29:17 am
No offense but you don't sound ready to tackle a ring and pinion swap on your own. Find a 73-87 C series 5 lug axle with the ratio you want and swap it in.
Title: Re: Need help
Post by: Irish_Alley on May 13, 2012, 10:42:36 am
(http://www.naioa.com/v2/modules/Forums/images/smiles/iamwithstupid.gif)
Title: Re: Need help
Post by: gto109 on May 13, 2012, 04:18:50 pm
I agree with Vile. 
Title: Re: Need help
Post by: muddjar on May 14, 2012, 12:05:17 am
I have looked for one they all have the same gears in them. Do I get a 30 spline will it work or will I have to change axles
Title: Re: Need help
Post by: Irish_Alley on May 14, 2012, 01:56:42 am
splines dont matter with a axle swap
Title: Re: Need help
Post by: bake74 on May 14, 2012, 06:20:26 am
splines dont matter with a axle swap

     As long as you swap out the whole axle, the only thing that could be different, that you would need to check is the yolk that the drive line hooks up too. (the one coming out of the front of the pumpkin on the rear end, as long as it is the same class of truck as yours, ex. 1/2 or 3/4 or so on).
Title: Re: Need help
Post by: muddjar on May 14, 2012, 02:59:54 pm
I was told that I could use a 4 wheel drive rearend and find some some 12 bolt axles and that would work but it as just more to it.  They told me the ones to match up. Because I've got the 28 spline and the 4 wheel drive has 30 and the 4x4's r longer
Title: Re: Need help
Post by: Irish_Alley on May 14, 2012, 05:53:23 pm
que? all 73-87 are the same lenth. you can use a 4x4 rear axle. a 4x4 10 bolt is the same as a 4x2 10 bolt. its a direct swap the only thing
Title: Re: Need help
Post by: Irish_Alley on May 14, 2012, 08:03:10 pm
just thought of it 4x2 are 5 lug while 4x4 1/2ton are 6
Title: Re: Need help
Post by: VileZambonie on May 14, 2012, 09:17:28 pm
Where are you located? Where have you looked for a rear end?
Title: Re: Need help
Post by: muddjar on May 15, 2012, 04:13:43 am
I'm in central Arkansas. I'm going to hit some more junkyards and c what I can come up with. I ran the Vin though Chevy and it came up showing that my gears were 9 half ring with 342 gears at least that's what she started with
Title: Re: Need help
Post by: bake74 on May 15, 2012, 06:27:09 am
I'm in central Arkansas. I'm going to hit some more junkyards and c what I can come up with. I ran the Vin though Chevy and it came up showing that my gears were 9 half ring with 342 gears at least that's what she started with

     Have you tried a local ring and pinion shop or the like to see how much they would charge for repair ?  Might be cheaper and less hassle to get the one you have fixed.