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Help needed rebuilding Eaton G80 Gov-Lock. Parts available? Manual?

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CheyenneKid

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I have open diffs in my 12 bolt, and need a traction aid. i like the performance in my bros. G80, and despite it;s reputation as being a weak sister, bought one on the eBay. Well, it looked like it was in good shape until I got it home, where I found the inner ring gear stripped up a little bit.

At least I got my money back and got to keep the locker.

Do I throw this away?

Do I rebuild it? Info seems a little sparse.

Do I bite the bullet and get an ected instead? An ARB?

See, I live in upstate NY where we have ice and snow in quantities, where an open diff is preferable most of the time at speed. Real lockers are SPOOKY at speed on ice. I need something selectable or something that acts as an open too, and a posi just don't cut the mustard.

I'm only going to run 33s, and I'm not really heavy footed (stock 350 TBI, SM465/NP205, 3.73'ed 12 bolt rear, 3.73 10 bolt front, mature driving style.) so's the durablity (or reputed lack thereof) of a g80 is not particularly important, unless it is dismal.

I need help. Thanks,

CK
 
Hello, Why don't you get a Lockright or Detroit EZ locker If you have an open diff you pull the spiders out and slip these right in. Have fun!
 
A friend of mine just removed the gov lock pieces out of his diff. and it is now just an open diff.

I have no idea what he removed to make it a functional open diff. though?

This may be all you need to do since you seem to prefer not to run a locker

Have a look , it may be as easy as it sounds?
 
Detroit Tru-Trac in my opinion is the finest limited slip out there, works flawlessly and you won't know its there until you make it work for you

the factory G80 is miserable it will blow up on you just for fun and cares not that you have maintained it and have an easy driving style
 
Those lockers are OK, but I need open too. Ice makes driving them pretty hairy at speed. I only need the traction aid kbelow 10MPH.

Thanks
 
I think ideally, I'd like to repair the gov-lock, I have open diffs already.
 
Have you used it on ice and snow at speed? The detroit I drove in a full-size k10 understeered and walked sideways at speed whickh i consider unnacceptable behavior at highway speeds. Would a trutrac alleviate that prob?

CK
 
the tru-trac is not at a like a full up detroit (no-spin) locker it is a gear driven limited slip unit, I have driven in the snow/ice with one and had very few issues with it, you do have to drive it like a locker as far as staying off the gas in turns becasue of its excellent ability to do its job... it will send power to both wheels all the time unless one wheel has an excessive amount of traction, then it will give.... one of the reasons I loike this diff so much is that it doesn't require addatives in the oil and doesn't have friction plates to wear out

if that is still too much traction for you consider an auburn sure-grip

I should also note that I am from southeast texas and do not drive a full winter season in those conditions so my opinion should not be the only one you consult on the tru-trac, I have lived in parts of the world where snow/ice were an issue and had the tru-trac in the rear end of a 4wd '91 burb and felt comfortable with it at all times but my driving style in snow/ice is very conservative
 
To answer your question about rebuilding Gov locks. Yes you can rebuild them.
You can get the parts from Randys Ring and pinion:http://www.ring-pinion.com/ i have bought diff parts from them they are good people and have everything i ever needed.

Here is a pretty good online guide to rebuilding a GU80. http://www.fullsizechevy.com/fscu/eatontech/
I highly recomend using heaver springs to cause it to lock up sooner. The sooner gov locks lock up the better. Their main weakness is having wheel spin then suddenly locking. It tears stuff up inside. Thats prolly how the gear got stripped in the one you have. Too much torque sudenly applied can also crack the carrier in two.

Is the GU80 dismal? No i dont think so. I have 10 bolts and run one in the rear with heaver springs installed. I run a lockrite in the front. I have 33s and 3.73 GR. I would not run tires bigger than 33 with a Gov Lock. I have had no problems with this combo as a matter of fact I like it. Because i have the street manners of the Gov lock plus the traction of a locker in the front to take some of the strain off the Gov Bomb. It has worked well for me for many years and I beat my K5 when I have to and drive 44 miles a day thru ice and snow on the interstate all winter.

Yes there are far better locker/posi units out there if you have the cash then get one. Detroit, Eaton, and Auburn, all make LS/ Posi traction units that will work for your needs. But if you are easy on the skinny pedal and use the power knowing how a gov lock works a gov lock will last. The fastest way I know how to blow a gov lock is mashing the throttle and trying to light up your tires around a corner. But eventually if you do it all the time that will kill almost any clutch type locker :D
 
Unfortunately, that's not a gov-lock. G80 is GM's generic "traction aiding diff" RPO, so that covers pretty much any LS/locker GM used.

CK, you might as well throw the thing away.

I can't recall if I posted it here or not, but there is a kent-moore tool specifically designed to pull the gov-lock apart, believe me, you need it. I tried to make one, but you need hardened steel. The pieces are in there so tight that the tool I made both bent AND was eaten into by the parts I was trying to move. BTW, that Kent Moore tool is over $200.

GM dealer told me they *used* to have that tool, but as with everything throwaway anymore, they were told a few years back to not waste time rebuilding one, just replace it. Might be worth calling your local GM service department and see if they still have one around you can use, but I kinda doubt it.
 
I took the gov-lock from my S-10 apart just using a hammer and punch to remove the pins. I looked at the pics of the special tool in the manual and decided to try the punch. About 3 good whacks each and out they came. :cool1:
 
Thanks for the info! Yes, it is a Gov-Lock, I can see the mechanism which is quite different than a regular GM posi. I'm going to give Randy's a try, see how much it would cost to get thing together right. I hadn't even thought of them. I'll bet if I can get it apart I can get it back together.

You're right about the spin speed immediately before the lock-up in a gov, I was just up in the Maine North Woods with my bro's '91 :burb: running through some cedar bogs: when that locker engages, POW! TRACTION! It's pretty violent, specially when you're on the go pedal, but pull like a tank. The springs are a mod I definitley will be using.
 
Dorians post made me think......... sometimes the old brain cells dont click so good anymore.
The pics in the link i gave you to Full size chevy are not a gov lock as most people know them. That is a Eaton Posi which is a good unit and can be rebuilt easily. They are also way stronger than the "Gov lock cuz the carrier is made out of nodular iron insted of cast as the Gov locks are made out of. If you have the unit shown in the pics you can rebuild it.
If you have the Gov lock with the thingy on the shaft with the fly weights that goes acrost the opening in the carrier. they are quite a bit harder to rebuild and need the special tool. Most people just throw them away and get a new unit.
I have the eaton posi unit as shown in the pics. Not the gov lock.
If you cant see any big springs between the side gears when you look into the openings in the carrier you have the gov lock
Sorry if i gave you some bad info.
 
That "POW! TRACTION" you describe is exactly why the gov-locks are NOT a good differential, at least in the 8.5"/12 bolt axles. That locking action splits the carrier in half, which has happened to numerous people on this forum, myself included.

Even the 9.5" diff (14SF) I bought had a broken gov-lock, although the teeth were stripped. The "new" one is randomly locking up on the street though, and it's soon to go I'm sure.

As to Harry's comment on banging them out, I tried that on the 9.5", and succeeded in screwing up the shoulder that is machined into the shafts to allow the tool to get hold of them. I felt that anymore force would just bend the shaft. The design may be enough different on the smaller carrier that a different method would work, or that my carriers pieces were just in there exceptionally tight.

If it's already damaged though, can't see how you could make it worse by trying the cheap/easy disassembly! :)

I talked with Randy's about replacement gov-locks, the salesman told me they won't sell replacements. Maybe they'll sell pieces, but they certainly didn't want to take responsibility for the whole assembly! GM does sell the rebuild kits still, I'd expect for the 8.5" as they do the 9.5", and it will probably be cheaper than Randy's if purchased from gmpartsdirect.com
 
Thanks for the heads up. Stopping that slipping wheel from spinning takes a lot of force, evidently not what this unit is up to. I checked out the link, I do have a gov-lock with the "thingy", not the springs like a conventional posi. Unless I get some more encouraging testimony, I will be giviing up on this unit.

Thanks, CK
 
Yeah, the theory is really good, but even in the 14FF, people have broken them. Much less likely, but who wants to go with that axle if you just need a good locking diff? :) When they do work right though, they are great.

I'm contemplating my next step, I'd almost like to try a few different types of lockers and see where it gets me. I still think that for my type of driving, an Eaton flat plate clutch style with stiff springs (as pictured previously) would be the best choice.

Do a search on here for gov-locks and carnage, there are plenty. :)
 
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