Differential Help

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Nick Spicer

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I have an 1988 gmc R3500 crew cab single wheel. 5.7 350 engine. Automatic. 14 bolt rear end. the ring gear has 12 bolts. I have the differential out to rebuild and am looking for the internal parts but cant find them. looking for help on where to get the spider gears and parts to rebuild it. The spider gear has three legs. Thanks for the help
 

nvrenuf

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If the center pin in the diff only has 3 legs then you have a Gov Lock locking differential, it's good when it's healthy but destined to fail. I'd try East Coast Gear Supply for parts. Parts may be hard to find because many times folks scrap that diff and swap to an open carrier with a more dependable aftermarket locker inside.
 

1987 GMC Jimmy

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Also look at National Drivetrain. They have a store on eBay.
 

Nick Spicer

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Thanks so much! This is what it looks like.
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Nick Spicer

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What would be a good alternative to the gov lock? Yukon dura grip? Eaton? Just looking for normal everyday driving and reliability. I don't get crazy with it.
 

RoryH19

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Interesting. This must be FF.
Here is a pic of my 12 bolt.
Is also the same setup as my 14 bolt SF.

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nvrenuf

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Interesting. This must be FF.
Here is a pic of my 12 bolt.
Is also the same setup as my 14 bolt SF.

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The axle in your pic is a semi floater (SF), not a full floater (FF). Full floater axles have hubs with 2 wheel bearings like the typical GM front axle. You're right though, same set up - that is a Gov Lock differential also.

@Nick Spicer your breakage is why the Gov Lock is not preferred or a design copied by other manufacturers. The diff needs centrifugal force to actuate that "butterfly" which will open and grab the tiny teeth on the spider gear in the first pic. As you can imagine, engagement can be violent for such small parts.
 

Nick Spicer

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Mine is a full float rear axle
 

RoryH19

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Mine is a full float rear axle
I thought so since it looks nothing like my 12 bolt or 14b SF with gov lock.
Found a pic of my 14b SF

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