Confused on my rear end

[HeavyChevyShtbox]

I have a 91 k2500 HD 7.4/4l80 (8600 8 lug) and I did a diff service last weekend and I realized that I may not have the rear end i thought, it doesn’t look like a g80 (where you can see the spiders) it instead is fully enclosed and has 3 pairs of rods going horizontal that are each about 3/4-1 thick with retaining clips on the visible ends. Seems heavier than a regular 10.5 diff. I’ll be able to get photos this weekend when I replace my rear brakes and bearings. It is a FF rear end and the fella I picked it up from is the original owner and he doesn’t remember swapping the rear end. Any help or reference photos appreciated. I very well may just be confused on what a g80 looks like as it is in the RPO codes.

 

[Cadillacmak]

I have a 91 k2500 HD 7.4/4l80 (8600 8 lug) and I did a diff service last weekend and I realized that I may not have the rear end i thought, it doesn’t look like a g80 (where you can see the spiders) it instead is fully enclosed and has 3 pairs of rods going horizontal. Seems heavier than a regular 10.5 diff. I’ll be able to get photos this weekend when I replace my rear brakes and bearings. It is a FF rear end and the fella I picked it up from is the original owner and he doesn’t remember swapping the rear end. Any help or reference photos appreciated. I very well may just be confused on what a g80 looks like as it is in the RPO codes.

Does it look like this?

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[HeavyChevyShtbox]

Does it look like this?

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Nope, it’s fully enclosed and you can’t see the gears at all, it’s not an air or e locker either, both wheels spin during a burnout but it doesn’t hop when turning sharp either

 

[GoToGuy]

If you have a G80 , RPO in the glove box production decal you have an Eaton locker. It has flyweights and small clutches to engage both wheels . Then kicks out above 20 mph.
As you said you don't have the basic open ring gear housing with holes and visible spider gears . Your axle was of last production prior to GM spinning off axle production to AAM ( American Axle Manufacturing )
If want to how it functions , the OE service manual chapter 4 section B.

 

[Schurkey]

As you said you don't have the basic open ring gear housing with holes and visible spider gears .

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The 10.5 "open" differential doesn't have much for "visible" spider gears.

Neither does the TrueTrac:

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I've never seen a 10.5 Gov-Lock, though. Based on the service manual illustration, there'd be no side-gears visible on it, either.

If that differential isn't open, and isn't a Gov-Lock, I don't know what it is.

 

[FullBlowncustoms]

Gov-Loc was a Eaton early years.? Was it 14 bolt like a SS454? IDK? just asking...

 

[Schurkey]

ALL Gov-Locks are made by Eaton. GM--and now AAM--buy them from Eaton for installation in the axles they manufacture.

The SS454 was a 9.5" axle, semi-float. OP says he has a full-float axle in an 8600-lb GVW truck. Therefore 10.5".

 

[b454rat]

Govlock in a 14ff is a 2 piece case, and can see the clutches looking at one of the holes.

 

[ChrisRHC]

You can't see the spiders with a full float rear, the entire mechanism is encased in the carrier housing.