looks like they are hated and loved equally.

local scrapyard sells the complete axles for 35 bucks.

i've read good and bad about them and can't really make heads or tails because as with most "bad" info, it's usually missing pertinent info such as the conditions under which it grenaded, etc.

was at the local scarpyard this past weekend and spotted a like truck with the g80. since the vehicles are lifted of the ground, and this one not having the wheels or drive shaft, i grabbed the passenger brake hub and started rotating it by hand. after about half a rotation, the driver's side started rotating. also occured when spinning the hub counter clockwise.

i understand that the differential unlocks at about 20mph.

does it lock up from 0 mph? is it based on amount of acceleration?

thanks!

Knicknamed 'govbomb'. But I had great luck with it in my ZR2 S10.

If I just stomped on the throttle, it wouldn't lock. But if I eased into it, it would lock nicely. I don't know the specific inter-workings of it. But mine lasted just fine with 70k miles of daily driving and occasional flat-land wheeling on 35s.

A good rear axle out of those is pricey.  The G80 can be very effective when used within its limitations.  However its very design can lead it to failure.  It requires a certain amount of speed difference between both rear wheels to operate.  Basically more slip than you would ever encounter going around a turn, but it will not lock at speeds above roughly 20-30mph.  This it where it earned the name "gov-lock".  It has a speed governor that operates off centrifugal force inside to govern locking.  

When it locks, it locks hard.  Imagine one tire sitting still, and suddenly being launched to a speed of 20-25mph.  That takes a great deal of force and puts a lot of strain on internals.  They have a tendency to break with no warning.  Some folks get one that seldom operates as they think it should, while other people are quite happy with them.  I think it has to do with expectations, production variations, and driving style.  I've had some that worked great, some not so much, and one that made a bunch of funny noises as it was eating itself.  

Replacement parts for a G80 are a joke.  You can buy a brand new detroit truetrac and installation kit for less than the parts to repair a G80, even at employee discount prices.  

If you have one and it works, great.  If you don't have one or it needs repairs, the aftermarket can provide a better solution.

What he said.

They also don't take well to getting stuck and rocking the vehicle like a mad man.  Usually ends with a broken axle shaft.

How are them ZR2's? I've been thinking about downsizing.

You'll spend as much time repairing it as driving it, but it can go anywhere a jeep wrangler can, usually a tiny bit further.    I had a blazer ZR2, and it would surprise me with the things it could do... and once in a great while it would surprise me with what it couldn't do either.  I miss it.  Gas mileage is horrible.  Something like 12mpg city with a/c on and 16hwy, bone stock.

I hate them.  

If you can drive slow in slippery road conditions and have good tires for said conditions, then I like the fullcase Detroit Locker for rear applications.    Other wise a good LS is nice.  I prefer a plain old clutch LS like the Eaton and Ford units, just shimmed up nice and tight with no friction modifier at all.  

I don't like the TrueTracs as they wear and are a bit fragile.  I've seen a couple fail in a Mustangs axle (kaboom).  And one fail in an 8.8 installed into the rear of a Ford Ranger (wore out gears, no LS action, sometimes would lock up at odd moments)

But we're talking about junkyard axles and such, right?  In that case toss that axle in and see how it works for you before making changes.

My ZR2 has the G80 and I have had no problems and I use it pretty hard. My M1009 has the G80 and I have also had zero problems and it is 25 years old. I also have a M1028 with a Detroit locker in the back and the Trac-Loc in the front, it is a whole different animal but I enjoy it also. The G80 in my opinion are a great daily driver locker if you cant spend the money on something like a ARB locker.

the govloc(truck G80) is decently strong in the 14 bolts(9.5 and 10.5 versions, sf and ff)  but pretty weak in the 10 bolts(7.5/7.65 and 8.5/8.6)

As the owner of 3 different trucks with G80's,  I would tell you these things:

If it's in a 8.5/8.625, it will blow up eventually.

When will that happen? I really wish I could tell you. Some just die quietly in the night, never to lock again, and others like to go out with a bang. Literally.  You may get the elusive 3rd option, where it simply won't die, even with pounding. My G80 in my '00 I sold to my dad had been locked, jumped, put under rapid stress, brakestands, donuts, 35" tires for 45k miles, mudding, hill-climbing, etc.  

The G80 in my '00 must have been forged by Jesus, because I've been a member of FSC and GMFS for ~5 years now, and have seen some G80's go with regular driving.

If it's in the 14-bolt (9.5, 10.5), then it will be a lot more robust, but still prone to dying under the right conditions.

so from what i am gathering, my best bet would be either a lock-rite or true trac?

these are drop in and go?

i wish i knew as much about differential as i do about the rest of the truck.

p.s. i am wanting this for regular duty. no off roading or anything strenuous. just the occasional situation where limited slip will save me from having to call a tow truck or a friend...

on a trip to the scrap yard yesterday, i did look at a couple 95 s10 blazers that had the rear differential cover off. according to the rpo codes, both were g80.

they look like different units to me.

at 40 bucks for the whole axle, which, if either, would be the one to pull?

2nd pic looks like a open diff.

lol, see, that's what i know about them.

if that is the case, then the rpo sticker in the glove box was wrong or rear axle was swapped, and it's surely the latter.

All the second one has is a set of spider gears and the carrier. When you make a "Lincoln Locker", you take a welder and weld up those spider gears to create a locked axle, hence the word "Lincoln", IE, a well known welder manufacturer.

while i was at the scrapyard again today, i looked at the one in the first picture. it's a 7.5.

i rotated the passenger side hub by hand slowly and the driver's side rotated the same direction, meaning, both wheels went the same as if the differential was locked up.

is that normal because the cover is off and is dry? or does that mean there is a problem?

Another gov-bomb

nice, what were the conditions under which that let go?

see, i keep reading about them being weak and letting loose, but it seems comparable to bad restaraunts as you always hear more about the bad than the good, or better yet, the quadrajet. rochester made how many million and because several hundred hate them, they are all bad?

but, my intention is to just have some kind of limited slip mainly for the occasional traveling some dirt roads into the desert to shoot and hunt. it will be behind the 2.8l v6 and a 700r4. no interest in getting one to do burn outs or heavy offroading.

5.3 l GMC 2wd

Stomp rolling 15 MPH slight right turn downshift BOOM!

The Eaton G80 in my Z71 Tahoe seems to work just fine.  I had to go through a ditch to park somewhere the other day and as the truck was twisting, the RR tire lost traction and started to spin...CLUNK...locker locked up and rode right up the other side.  I think they're pretty cool.  Some neat vids:

G80 Twist Ditch

G80 20% Grade

I like this one...

will check out those videos.

is there anything visible that i should look at on the g80 pictured before i spend the time pulling the axle out?

i don't recall seeing many covers removed at the scrap yard and this one had been, which makes me wonder what was being looked at by the person who removed it.

the gear ratio is 3.73 as shown by the rpo codes.

2.8 auto.....buy with confidence. You're not gonna be stressing any drivetrain components.


As to 4x4 s series rigs in general. I wont have another even if Jesus himself was giving it to me

that third video is pretty cool.

yeah, i don't think i'll be intentionally doing that kind of stuff.

Mine blew up in my k2500 454 suburban. It's a 14 bolt full floating rear end.

I was screwing around on the ice pulling a friends Jeep, doing donuts. Mashing the throttle going through gears spinning the tires.

I got a rebuilt unit for 300$. I know the gov loc has its problems, but also each wheel and tire weighs over 100lbs. That is a hell of a lot of energy for any diff to try to lock. It was my fault.

Always remember to just take it easy. No screwing around, easy on the throttle when only one wheel has traction.

That's one of the more spectacular ones I've seen. Congrats.

My caprice has the G80 code, but its not a locker, its a limited slip. It has clutches like a posi-track.

Yep, the g80 is kind of a cross between a locking diff and an open diff.

Btw, I was able to clean out the gunk in my diff and reassemble it as an open diff. Only I pulled a boner and what slipped my mind was that the clutches spaces out the side gears and when I put it back together the gears mesh was way off. I ended up stripping the gears out a few months later.