G80 is GM's RPO code for anything 'Limited Slip', what ever style of 'posi' carrier the vehicle is equipped with.
10B's, 12B's & the 14B's all use the same RPO code for limited slip, although parts between the 3 are obviously not interchangeable.
'70's GM muscle cars & GMT400's can both have a G80 RPO code, but the limited slip style of carriers are not the same.
'Positraction' is a term originally coined by GM but has become generic across the board. Most car-people know what is being referred to when using it.
GM used two styles over the years. A clutch/spring style & a 'locking' ratchet style. Both were made by Eaton.
The former uses coil springs & clutch plates. The amount of slip between the axles is regulated via spring pressure & clutch count/material.
The latter uses a ratchet style.
The ratchet style is wheel speed governed. Mechanical locking. Centrifugal force engages the pawl.
That pawl is the weak link in the design. When it lets go, it takes out the rest of the internals with it.
A Gov-lock can be unpredictable.
Locks up when you don't want it to or won't when you really do.
I would never replace a Gov-lock with a Gov-lock. Waste of time, effort & $$$.
There ARE clutch plates within a Gov-lock, but for the sake of description, the terms I'll use here are apparent in the pix.
What you have is the ratchet style.
Other people call them different names, but one day, sooner or later, they'll all call them 'Gov-Bomb', because...that's what they do. Usually at the most inopportune time.
The clutch plate & spring style is much stronger & way more predictable in it's performance, as opposed to that...bomb.
The C/S style is also totally rebuildable with options in springs tensions, clutch plate materials & clutch plate count in order to tailor the performance of the diff to your driving style or needs.
A G80 Gov-lock, 99.99% of the time, is not rebuildable, even if the carnage was minor.
It's performance vs. the cost of re-installing a duplicate can't be justified.
If you're spending the $$$ to get the diff rebuilt, why use an already proven unreliable part?
For similar $$$ a better, stronger carrier could be installed without that question mark in your mind, wondering when & where the Big-Badda-BOOM is going to
G80 Gov-BOMB.
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...eventually...
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Clutch, plate & spring type.
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My experience is with these.
I rebuilt my first almost...ehh...let's just say...that was d-d-decades ago. (ouch)
They're strong, simple, reliable & easy to work on, if ever. Once they're in & properly set-up, that's it. With regular maintenance, for years. Thousands of miles.
They'll put up with way more abuse and they don't catastrophically explode like the Gov-lock. Not saying that that would be impossible, but it would take some big power. Way more than what would make sense for a daily driver.
Other weak points of the 10B would show their heads long before the carrier goes boom.
The clutches wear and that's about it. Depending how hard you use the truck, 100,000 miles & more on a set of clutches is easily feasible.
Cheap & easy to rebuild.
I'm not nice to mine.
Mid-'90's Impala sedans (SS's & 9C1's) had these, factory. Fits our truck's housings. Same axle spine count.
Stupid tall ratios, though. 3.08, 2.73, etc.
The carrier will support down to a 3.73 gear set without the need for a ring gear spacer.
From the wreckers, $50-$75 for just the carrier or about $150-$200 for a completer rear end.
Complete because it's the same rear as a 400's, but about 3" narrower. (Low truck + wide(r) tires/wheels. HeHe!)
Irrelevant for your needs though.
...and then!
...and THEN!
There's the fact that you're where? Oxford U.K? Yikes.
Somehow I just can't see you happening to stumble across a mid-'90's Impala, let alone an SS or a 9C1 (cop car) in the local wrecking yard, let alone the whole of the British Isles.
There are lots of options when it comes to 'Posi' for these trucks.
Lots of styles & vendors.
Some are somewhat budget friendly, while others not so much.
The only limit is the depth of your pockets & the length of your arm.
But like I said. My exp. & yea, probably a bit biased. Not saying that these are the best, but they've always been problem-free for me & this abnormally large, out-of-proportion right foot.
Once less thing to worry about once that POS Gov-bomb was outa there.
Here's some info on the choices available.
There are some other members here with much more experience than I with the other types of 'Posi' along with knowing how each is suitable for the situations that the truck will be used for.
Hopefully they'll drop in here.
https://viciousoffroad.com/n-24-the...ked-vs-spooled-part-2-lockers-and-spools.html