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#1 |
Registered User
Join Date: Mar 2007
Location: Austin, TX
Posts: 292
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Rebuild or Replace?
My GM 12 bolt rear whines and moans. Sadly, my rear makes more noise than my exhaust now. I have popped off the cover for a visual examination, and the wear pattern is terrible, chips in the ring itself... This death trap is going to lock up someday so I need to have it rebuilt w/ new ring and pinion, or replace it with a junkyard find.
Rebuild or Replace? Factor in cost, effort, etc... Thank you in advance. |
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#2 |
78K & 79C Jimmys
Join Date: Nov 2009
Location: Ottawa Ont CANADA
Posts: 7,901
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Re: Rebuild or Replace?
i had mine rebuilt
somebody weilded stuff that they shouldn't i felt it was better to rebuild as other stuff would prob break replaceing used offset axle bearings when going back together,(new spot to roll on)
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John 1978 GMCJimmy4X4-350/203 1979 GMCJimmy4X2-305/350 |
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#3 |
Registered User
Join Date: Jul 2007
Location: Tucson, AZ
Posts: 3,188
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Re: Rebuild or Replace?
Why not just check out a used one. It seems to me that you could take the cover off and have a good look see on a used one. On the 3 squares I have owned I have never had any trouble with the rear axles, but they were all 3/4 ton trucks. I did overload them all on many occasions. In your neck of the woods old squares should be all over the place. Maybe you could score a whole truck with a good rear axle and sell/scrap the rest of the truck.
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#4 |
Laid back freak
Join Date: Mar 2008
Location: hastings florida
Posts: 248
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Re: Rebuild or Replace?
I had a spare 12 bolt n had it rebuilt.New gears, (3:73) a auburn posi, richmond rebuild kit.Also added disc brakes to it.It all depends on what your budget is.Do you want to rebuild it n feel safe or take a chance and grenading a rearend? Id go for the rebuild n feel more safe.
thanks pat
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1980 chevy c10 step side restomod, ![]() 1970 cougar convertible 1 OF 24 ever built: 2014 Hyundai Tucson limited (daily driver). |
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#5 | |
Registered User
Join Date: Mar 2007
Location: Austin, TX
Posts: 292
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Re: Rebuild or Replace?
Quote:
Last edited by veinbar; 06-21-2011 at 01:59 PM. |
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#6 |
Laid back freak
Join Date: Mar 2008
Location: hastings florida
Posts: 248
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Re: Rebuild or Replace?
Welll the thing is i went a lil overboard on the whole build itself since i wanted everything clean n powdercoated.You can rebuild it for probably around 3-400 depending on where you shop.But while your rebuilding it, and want a lil more pep you could upgrade the gears to like a 3.42 but dont go overthat cause youll be increasing the rpms more if you go to like a 3.50.If you are using it on the highway then the 3.08s are good.Im sure you will have them look at the ring n pinon for chipped teeth.
thanks pat
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1980 chevy c10 step side restomod, ![]() 1970 cougar convertible 1 OF 24 ever built: 2014 Hyundai Tucson limited (daily driver). |
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#7 |
Senior Member
Join Date: May 2004
Location: Caldwell,Tx.
Posts: 3,648
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Re: Rebuild or Replace?
Let me ckeck my parts truck . Its a 77 with a 12 bolt . I do not know what gear is inside but if it is a 3.08 gear , I will let you know .If it is nice and the right gear I would sell it .PM me in a day or two so I do not forget .
Frank
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Born and proudly residing in a Red State ! |
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#8 | |
Registered User
Join Date: Mar 2007
Location: Austin, TX
Posts: 292
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Re: Rebuild or Replace?
Quote:
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#9 | |
78K & 79C Jimmys
Join Date: Nov 2009
Location: Ottawa Ont CANADA
Posts: 7,901
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Re: Rebuild or Replace?
Quote:
3.73 rear end new brakes,e-cables,shoes,wheel cyclinders,.....and all the rest of the bits now after about 5 years ....had no issues.....good insurance ....no regrets...... beats walkin or drivin a ford lol
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John 1978 GMCJimmy4X4-350/203 1979 GMCJimmy4X2-305/350 |
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#10 |
Account Suspended
Join Date: Dec 2007
Location: Unnapreciative, Trollville
Posts: 2,079
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Re: Rebuild or Replace?
Cheapest thing will be get another completes axle (minus brakes) from the junkyard. Done it many times and never had a problem. just check inside the pumpkin before you buy it or get a warranty. Then put new wheel bearings in it and all seals except the pinion as long as it doesnt leak terribly and call it a day.
On a side note; the axles from a VAN will NOT work, they have to be from a squarebody for the spring perches to be in the right spot. |
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#11 |
Registered User
Join Date: Mar 2007
Location: Austin, TX
Posts: 292
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Re: Rebuild or Replace?
Just bringing this to the top again because I can't get a real estimate out of shops. I have a GM 12 bolt w/ 3.08 open rear. I want to rebuild it and keep the ratio the same. I will purchase a ring/pinion and complete rebuild kit and take it to a shop. What can I expect to pay in labor for a rear end rebuild? I will have approximately $300 or less invested in parts.
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#12 |
Registered User
Join Date: Nov 2008
Location: edmonton, alberta
Posts: 293
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Re: Rebuild or Replace?
I had a 3.08 open diff in a 76 with a t350 on it. In canada, they wanted 1700 to make it a 3.73 and change all the bearings and races and add an eaton posi.
In austin I'm thinking you'd pay about 1400. I got a 3.42 from a suburban and the only thing I had to change was the back rear cross-u joint to make it match the 10 bolt dif yoke. FYI.
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![]() 76 Silverado, 2wd, long box, 350/th350, 3.42 posi, edelbrock performer 64cc heads, edelbrock 1405, 2101 intake, Hedman Headers, Comp Cam XE262 http://beerbreadbike.wordpress.com/ |
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#13 | |
Registered User
Join Date: Mar 2011
Location: Medford, Oregon
Posts: 33
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Re: Rebuild or Replace?
Quote:
also, might concider the used rear end road...have had pretty good luck with "recycled parts" at the shop i work at, would save a bunch in labor
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79' GMC stepside...the money pit! ![]() 355 aluminum partoit heads 2.02,lunati 268 flat tappet,comp roller rockers 1.6,hi-tech torque link intake(Jim McFarland),electric water pump,650 holley double pumper,msd 6al,msd street fire dizzy,doug's long tube headers(ceramic),3" exhaust(flowmaster 40) |
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#14 | |
78K & 79C Jimmys
Join Date: Nov 2009
Location: Ottawa Ont CANADA
Posts: 7,901
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Re: Rebuild or Replace?
Quote:
and mine took 1 guy (not CTC)two days pretty much.....and with me watching/asking questions after Canadian Tire ran my 83 camaro into the lift, my truck or car dosn't go in a shop without me.....watching (that learning alone is worth $$)
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John 1978 GMCJimmy4X4-350/203 1979 GMCJimmy4X2-305/350 |
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#15 |
Registered User
Join Date: Apr 2010
Location: Ardmore, OK
Posts: 164
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Re: Rebuild or Replace?
Im about to have my rear end rebuilt in my '90 model K5. I took it to a very good shop here locally and they quoted me $350-$400 labor with me supplying my own parts. I thought this was pretty good. I currently have 3.73's in the blazer and Im switching to 4.56's since I will be lifting it and running 35" tires. The new ring/pinion set from Summit is $150 a set......dont knock Summits parts unless you have had a actual bad experiance with them, keep the "hear say" and rumors at the water cooler. Also, a complete rebuild kit is about $100 through Summit. Im changing out gears in the front and rear so it will be a little more, but just the rear end rebuild was $350-$400 labor.
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1984 K10 SWB "Coal" 1987 K5 Blazer "Ole Miss" 1979 GMC Jimmy (Project) 2008 F250 CC 4x4 King Ranch 6" lift on 37's (Spartan-ized!!) 2008 Dodge Challenger SRT8 Hemi Orange 2008 HD StreetGlide 2007 HD Custom Fatboy 1980 Suburban (will be for sale or trade soon). |
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#16 |
Registered User
Join Date: Mar 2007
Location: Austin, TX
Posts: 292
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Re: Rebuild or Replace?
That $1000-$1200 price tag is pretty cosistent in Austin, TX. It seems like most shops try to talk you out of doing a rebuild. I have a sneaking suspicion that overhauling a rear end is not a glamorous process, thus promotes lazyness in mechanics city-wide.
That being said, I have also checked into local junkyards. One junkyard has an '80 silverado 1/2 ton w/ a GM 12 bolt (3.08). Condition unknown, and I couldn't inspect it because they were closing when I arrived. I would like to return to the yard prepared... 1. How to I determine if a rear is good or bad? 2. Does anyone have a picture or video link that could assist me? 3. What can I expect to pay for a used GM 12 bolt rear? Thank you in advance. Have a great day. |
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#17 |
Registered User
Join Date: Jul 2011
Location: augusta, ga
Posts: 11
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Re: Rebuild or Replace?
getting my rearend done now and they quote me 600.00 to do it but i have to bring all the parts. that with a 3.73 gear , powertrax posi locker,new brakes, diff cover plus other things
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#18 | |
just can't cover up my redneck
Join Date: May 2004
Location: Columbus OH
Posts: 11,414
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Re: Rebuild or Replace?
Rebuilding is going to cost, plain and simple. The gears, bearings, seals, etc are going to be at least $250 and you are looking at a labor cost of at least that (probably more depending upon your particular part of the country)....So yo are looking at an absolute minimum of 5 bills.
From a strictly cost effective way to look at it, that is an expensive way to keep the same ratio and not add a traction device. If you are looking to do either of these up-grades, it becomes a different story.. Personally, I would recommend looking for a used rearend. It may take a little work on your part, but it will come out a lot cheaper. Inspecting the axle is not that hard, but you do need to do it to be sure of what you are getting. You want to be sure to pull the cover off and see inside. This will assure you of the gear ratio in the first place, but more importantly you can see the actual contact area of the gears. The main thing to look at, other than the obvious wear (metal shavings, etc.) is the backlash. That is the "clearance" between the ring and pinion themselves. Hold the pinion so that it cannot move and rotate the ring gear back and forth. It should move only slightly before it "hits" the pinion and stops. We are talking only a few thousands of an inch here, nothing crazy. If there is a lot of movement, it is excessively worn.....and there is no "fix". It is no better than the one you already have. While doing this you may come across an axle with a "Gov-Lock". It's a factory positraction unit. In a light duty application, they are OK, so it's not necessarily a "deal breaker".....but don't pay any extra for it. Even if the used axle does fail on you after a few years, it was cheap in comparison. Sure there is some work involved, but you can save quite a bit of money for your efforts. As always, synthetic lube is your friend here. Cheap insurance.
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You can review the site's rules here. Quote:
Bad planning on your part does not necessarily constitute an instant emergency on my part.... The great thing about being a pessimist is that you are either pleasantly surprised or right. ![]() |
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#19 | ||
just can't cover up my redneck
Join Date: May 2004
Location: Columbus OH
Posts: 11,414
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Re: Rebuild or Replace?
From my earlier post....
Quote:
__________________
You can review the site's rules here. Quote:
Bad planning on your part does not necessarily constitute an instant emergency on my part.... The great thing about being a pessimist is that you are either pleasantly surprised or right. ![]() |
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#20 | |
Registered User
Join Date: Oct 2009
Location: North Carolina
Posts: 151
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Re: Rebuild or Replace?
Quote:
I know he owns about a million 67-72 trucks and I think he has 73-87s as well. I just bought a great used 12 bolt rearend for 150 bucks but that was probably a rare deal. I see them on Craigslist for 300+. |
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#21 |
BAD BOW-Silverado XST
Join Date: May 2000
Location: Senior Member from Austin, TX
Posts: 6,431
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Re: Rebuild or Replace?
Call A-Ok Chevy Parts in Elroy. Elroy is a few miles outside of town. I bought a 12 bolt from years ago. Ron specializes in square body parts.
(512) 247-4268 140 McDowell Rd Unit B Del Valle, TX 78617 If you need parts or info in Austin, give me a buzz. Last edited by gchemist; 07-19-2011 at 08:16 PM. |
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#22 |
I'm back with 2nd truck!
Join Date: Feb 2002
Location: Texas
Posts: 3,775
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Re: Rebuild or Replace?
I took a 12 bolt from another truck and took it to a shop with a new complete kit minus the brakes and had it done for $75. This was going from 3.07 to 3.73 (yes I said 3.07 it shows this on the sticker).
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1979 Chevrolet Bonanza Big10 "Tootsie Roll" 1985 Chevrolet Silverado (wife's) Member of the Southern Bowties Club "Don't underestimate how sexy a fat man who drinks to excess can be." Homer Simpson |
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#23 |
Senior Member
Join Date: May 2004
Location: Caldwell,Tx.
Posts: 3,648
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Re: Rebuild or Replace?
Sorry for not getting back to you on my rear . It looked pretty bad inside . I looked at a 48,000 mile original 6 cylinder 80 model with a 12 bolt rear that the that the guy wants $250 for but it had a 2.76 open rear . I know you wanted to stay at 3.08. I have one other truck to look at . PM me this saturday and I will let you know what it has in it .
Frank
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Born and proudly residing in a Red State ! |
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#24 | |
Registered User
Join Date: Mar 2007
Location: Austin, TX
Posts: 292
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Re: Rebuild or Replace?
Quote:
I'll PM you just to keep in touch should a rear end come about. |
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#25 | |
Senior Member
Join Date: May 2004
Location: Caldwell,Tx.
Posts: 3,648
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Re: Rebuild or Replace?
Quote:
Frank
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Born and proudly residing in a Red State ! |
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