Rear axle replacement

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Pmcb

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That’s a good idea
 

Pmcb

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Here are some pictures. This truck had a perfect body before the axle came out.
 

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Pmcb

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My other photos are too large to post.
 

Doppleganger

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I dont know if any of these codes would be in the glove box on the SRO decal, but found this in the back of a Mitchell's guide I had (for GMC '87 4WD trucks).

GM8 2.56 ratio
GU2 2.73 ratio
GU4 3.08 ratio
GU6 3.42 ratio
GT4 3.73 ratio
 

DoubleDingo

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It looks rebuildable to me. Just need the parts.
 

RustyPile

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I count 12 teeth on the pinion - not 15.. The tooth count is stamped on the outer edge of the ring gear.... If that mark is not legible, simply count the teeth.. Divide that number by 12 and that's your ratio...

If your 41 count is accurate, 41/12 = 3.42.....
 

Turbo4whl

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I dont know if any of these codes would be in the glove box on the SRO decal, but found this in the back of a Mitchell's guide I had (for GMC '87 4WD trucks).

GM8 2.56 ratio
GU2 2.73 ratio
GU4 3.08 ratio
GU6 3.42 ratio
GT4 3.73 ratio
As far as I know, most years, the only time the ratio is listed, is when the vehicle was ordered with an optional ratio. The standard ratio that would be installed with each engine, trans and tire size, was not always listed.

A few more codes:

GQ1 -- AXLE REAR, STD RATIO
GT4 -- AXLE REAR, 3.73 RATIO
GT5 -- AXLE REAR, 4.10 RATIO
GU4 -- AXLE REAR, 3.08 RATIO
GU5 -- AXLE REAR, 3.23 RATIO
GU6 -- AXLE REAR, 3.42 RATIO
G80 -- AXLE REAR, LIMITED SLIP (POSITRACTION)
 

bucket

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Yep, another gov-loc did it's thing, lol.
 

Pmcb

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I came up with 3.42 as well Once I pulled it out to get a full look.
If I rebuild can I put a posi in? There is no difference in housing?
 

Turbo4whl

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Yep, another gov-loc did it's thing, lol.
Yes it did. Not made for hard use.
If I rebuild can I put a posi in? There is no difference in housing?
Eaton makes several different types of lockers for your truck. ELocker, electronic operation. Detroit Locker, hard core always locked, tight turn on a hard surface it clunks. Truetrac, will not always work well in reverse, very smooth operation forward. Eaton posi, clutch type.

Eaton also makes more types as well as several other manufactures. Lots available for your truck.
 

Ricko1966

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Here are some pictures. This truck had a perfect body before the axle came out.
All you have to do is count teeth and do the math I can probably count them from your pics. BRB going to try.
 

59840Surfer

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I was going to say, both axles coming out is likely from a broken carrier. Axle C-clips can't just fall out unless something else goes wrong. I'll bet the truck is equipped with a G80 Gov-Loc as well, which is why it all went kaboom. People like to talk about how the 10bolt version of the Gov-Loc isn't as bad as folks make it out to be, but it didn't get the nickname of "Gov-Bomb" for no reason.
The "gov-bomb' name comes from idiots spinning one wheel on ice or snow and the other tire on good traction. The little gears go crazy and ka-boom.



I got over 150,000 miles on one of them hauling logs, jumping stumps and running in snow and ice hauling 3 cords of firewood up and down offroad areas for years and until I just recently broke some teeth off the side gears --- it's been rfine.

An idiot - however - can kill a brick.
 

59840Surfer

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All you have to do is count teeth and do the math I can probably count them from your pics. BRB going to try.
Does anyone know what an RPO code is for?
 

bucket

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The "gov-bomb' name comes from idiots spinning one wheel on ice or snow and the other tire on good traction. The little gears go crazy and ka-boom.



I got over 150,000 miles on one of them hauling logs, jumping stumps and running in snow and ice hauling 3 cords of firewood up and down offroad areas for years and until I just recently broke some teeth off the side gears --- it's been rfine.

An idiot - however - can kill a brick.

Yeah, a lot of them hold up, there's no arguing that. But many have exploded just because the normal average person makes a normal average turn on dry pavement and happens to be applying a light amount of throttle like any normal person would be doing. Several times I've seen it happen on Tahoes and Suburbans that were never used for hauling or towing, just a life of hauling some kids around.
 

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