I have an '88 Firebird, running a LO3 (for now; TPI and/or 350 in future), WC-T5, and a 4th gen (2000) v6 rear axle with 3.08 gears. I've spent the past couple days and two hours today, and all the threads that started out exactly what i wanted to know, ended abruptly with no more responses. Also looked through the tech articles, but that doesn't seem to be where I'm going with this.

Alright, done the research, understand that i share the same 10 bolt housing as S10/Blazers, and Sonoma/Jimmys. I understand that with the 4 wheel drive systems in those vehicles, a lot of times, they had decent gear/posi setups. I understand that the axle i am using has 28 spline axles. So this leads me to the few questions that i have been searching for:

- what year pickup/suv mentioned above have 28 spline axles? Also which
years had a better posi?
- what is there to look for, i was thinking 3.73s, but should i look for 3.42
for any reason?
- are the same RPOs shared by 3rd gen decifers, or is there a source
someone knows that will give me a list to identify in the junkyard what
is what?
- how to tell physical condition of posi by looking at it?
- can i take the vehicles vss/speedo gear out and transplant it into my T5?
(even if it has the A4?)

i understand VAGUELY the differences of 2 and 3 series setups, but i will be picking up the entire axle from the donor vehicle. Is this everything i need to change from my 2 series to a 3 series?

Looking for a budget build, and possibly some experience shared from those who may have done it before. Also before someone brings it up, i do understand posi and l.s. is one in the same. Thanks for your help!!

Jon

 

The trucks used the Governor Lock differential, which is allright in a truck, but not too good in a performance car. They have many small parts in them that break easily. I don't recommend them for an application like yours. The Eaton posi is the best all around performance differential in my opinion.

If you still want to go for a truck differential then yes, the RPO code G80 applies to the trucks too. The gear ratio codes GU6 for the 3.42 gear and GT4 for the 3.73 also apply. All of the 7.5 rear ends were upgraded to 28 spline axles at the same time, around '89 or '90.

The 7.5 case series break is at 3.08 for 2 series and 3.23 for 3 series, so anything with a 3.23, 3.42, 3.73 or 4.10 will work for you.

 

I would love to use something else, but i don't have the money unfortunately. If i was to do normal driving, no burning out, doughnuts, ect. What would be the life on the unit, and would i notice the benefits of a Gov Lock? I just have a pick and pull with cheap rear axles and plenty of these trucks.

Is there a way/website that will tell me what i will have in 5th gear on my tach at highway speed. I want to have something with a decent acceleration, and maintain decent MPG. That would probably ultimately make my decision on 3.42s or 3.73s.

So your saying if i get the ring and pinion, i can change between 2 series and 3 series respectively. Just want to be sure that i understand the 2 and 3 series differences correctly.

Ok, if i was to find a posi/ring pinion set from a 4th gen, visually is there a way to tell the condition of the unit. Is there a way to rebuild them if i do find a good priced unit? What year 4th gens come with the Eatons as i remember reading some years had them.

Also any help on the VSS/Speedo gear info. I've found the info on what color to get, different tooth combinations, but no word on if i can take the one from the donor vehicle i'm getting the gears from. Thank you for your help!

 

The Governor Lock can be rebuilt, but it requires a special tool to remove the governor. The first thing to inspect on one of these is the small gear that runs the governor. If there is even one tooth missing from this gear set then it will not operate and will act like any other standard differential. Also check for chips or flaking on the axle and pinion gears in the differential. This differential will hold up fine as long as you don't abuse it much. A few burnouts will probably be all right. An automatic transmission would be easier on it than your 5 speed. You need to know that the Gov Lock will not lock up after you are moving, so stomping on the gas at 10-20 MPH may get you a lot of smoke from the right tire, but not the left.

As for the gears, you need a 3 series differential for 3.23, 3.42 and 3.73 gears. A 3.08 or 2.73 will require a 2 series.

The 4th gen Camaro and Firebird used a Torsen differential as far as I know. I don't think any of them had an Eaton posi. These used worm gears instead of clutches to limit slip. I don't know about the strength or wear on these.

Sorry, can't help with the VSS.

 

so i have a 3.08 axle right now from a 2000 axle...does that mean i'm SOL to go higher in gears outside of going out and getting aftermarket setup?

 

No, all you need to do is get a 3 series differential. The housings are all the same. When you find the gears that you want they will be on the correct differential. Just swap it all over into your housing.

The only difference between a 2 series and 3 series is the location of the ring gear flange. You can see the difference in this picture of some 12 bolt Eaton differential cases. The one on the left is a 2 series and the one on the right is a 4 series.

 

ok, thats what i thought, but i just got confused. So ring/pinion/diff and i can swap from 2 series to 3 series. Got it. Now that you've put a name to the type of posi offered in the S series trucks, why is it also known as "grenade-loc," ect? I mean outside of the "little parts" as you worded it, what makes this a very poor choice for my firebird. I mean my thoughts behind this is that the posi for a heavier, bulkier, possibly towing vehicle...would be a little more durable in a normal use vehicle like mine. I've gotten past the burnouts, doughnuts, and aimlessly wasting my money on new tires and parts. So at most this may see a chirping start at a light once in a while, smooth/cruising shifting 85% of the time, no dumping clutch at all, and maybe a little drift here and there on a wet day. Gov-lok is really going to blow up on me and stop working?

Can you point me towards this special tool that is needed to operate on this unit as well if you know it off the top of your head, or at least what it's called so i can further research it.

I just want something that will give me a little more traction, i have an uneven driveway with gravel and with the open 3.08 i get a nice 1 inch deep rut at the end of my driveway everytime i try and pull out.

p.s. thank you for the visuals. they are very helpful in showing what we are talking about. half the threads i'm looking at have all the pictures deleted.

 

ok, just found all the reasons not to use a governer locker. I still don't understand it completely though. Why would GM continue using such a thing if it was a POS??? Outside of cost, the way it was explained, it sounds like the firestone issue all over again. That going around a turn it it locking up could be unsafe, but the assumption that it's in an SUV with ungripping tires substantiates that?! as apposed to a "performance" car with grippy tires.

Curious....anyone using the Governer Locker's from an s-series truck, how is it working for you guys???

 

I though SLP has a posi unit for 4th gen cars for something like 100$. You might want to look into that, or if your just going to the JY and pulling stuff out, try finding a SS or a TA with a manual tranny, they came with 3.42"s and Posi. Thats the exact rear i pulled for my car. I would go with the Torsen unit over a gov-loc unit, they used to put gov-locs in our cars for a year or two and when they break its not fun, to my understanding. Even if you do not beat your car up things can break, its just the luck of the draw.

 

can you point me in the direction of that SLP thing your speaking of please. This pick a part doesn't have those kinds of cars unfortunately. It's had in the last 2 years one 99 v6 camaro and a 00 v6 firebird. Other than that, no v8 f-bodies unless they are mangled and beat to crap 3rd gens.

 

SLP hasn't had those for years now. They were take outs from new Camaro's. I got two, and a week later wanted another one but they were all gone by then. This has been a least 4 years ago.

Occasionally they come up on Ebay, and also pop up on Craig's List now and then.

I just pulled my 3.42 axle out with a zexel and replaced it with a 3.73 and eaton posi.

 

figures....thanks for the input.

 

The tool for the Gov Lock is sold by Kent Moore tools. I bought mine about 10 years ago and it was about $130 back then.

The Gov Lock might be fine for your use if you are not going to be hard on it. The Gov Lock was made for wet boat ramps, mud puddles, gravel roads and that kind of stuff. They aren't made for serious off road use. I doubt that you will be able to do much drifting with it because it just won't lock up when you are already moving at that speed.

Here is an example of what can happen to the Gov Lock in an extreme case. Scroll down to the 6th post and look at the picture of what use to be a Gov Lock.
https://www.thirdgen.org/forums/tran...nforce-my.html

 

Don't be discouraged. A short time ago I picked up a 02 LS1 axle with the much sought after LS1 style rear disks and a zexel. Got it for off Craig's List for $275, pulled the brakes and sold the axle and posi. All I wanted was the brakes.

They are around, just be patient and keep looking. Might try the LS1 forums classifieds also.

 

wow, i don't know, all these people that keep saying they are blowing the gov-locks are always talking about spray. And even then, on the thread that you just gave me, he said that he had it last him 3 years. But then i'm seeing threads talk about the whole setup grenading and sending shrapnil into the gas tank and what not. I'm just suprised that they would still be using this type of limited slip in say a 2000 s-10 or blazer, when these trucks are developed to be faster and what not, it just seems like maybe it was oversimplified when i read this one thing. It basically said that around a turn that if one wheel slipped that it could end up grenading the internals and intern may lock up the axles, which could lead to it's own issues, and being an SUV/pick up, with the higher center of gravity, just doesn't seem sound to me.

On another note, the people that are usually saying bad things, not just warning to stay away from them, but the people actually really complaining about how much junk they are, are the people pushing 350-383 TPI with their built 700r4, complaining that the gov-lock can't handle 400-500 hp. I know i'm oversimplifying things, and not having experience with them does make my arguement difficult, but just trying to understand. I thank you for your patience and knowledge sharing!
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yea, i'm going to be doing things over winter time, so i will have some time to look at this. I just remember seeing that the ring/pinion/diff all worked from the s-series vehicles, and figured finding higher ring and pinions was simple enough, that having the stock LSD would be beneficial. I will keep my eyes open, and not be quick to purchase.

 

Go make an account on Ls1tech.com, i did it just for their classifieds, they have stuff like that all the time for sale over there. Just be patient, you will find one eventually.

 

yea i made an account there not too long ago. i will be on the look out. Thanks!

ok, here's another question now that i've been talked outta the gov-locks after reading that much more about them, are the gears fine to grab? what is there to look at to make sure i don't have problems down the road (i understand i'm looking at used...just asking for anything obvious).

Also, anyone know anything about the VSS/Speedo gear, can i take one from the donar vehicle that i get the gears from? Does it matter auto/manual? Any details are appreciated!

 

Are you asking if any set of say 3.42"s is good to grab? Like if you took them from a truck or a camaro?

 

Yes, the gears would be good. It is more dificult to set up a set of used gears because the contact pattern is hard to read. It can be done, but not exactly a job for a beginner. Some people don't bother with setting the pinion depth when they swap in used gears. They just use the original shim and let it go. They set the backlash close and hope for the best. Many times this works out fine, but sometimes it ends up with a noisy gear, or a broke gear.

 

it wont matter, but i wouldnt swap in used gears when new gears arent that expensive. any beginner can swap in new gears, it isnt that hard, aslong as you have the right tools.

 

what is a good source to find reasonably priced gears? Better yet, what is a good reputable company to look at. I see the ring and pinions on ebay, but obviously being a first on this, i don't want to buy crap and have to do this again next winter.

If i was to find a deal with a ring/pinion/LSD, should i swap that in, or still end up getting new gears and using the LSD? I just don't want to go out and spend almost $1000, i don't mind spending a little coin, just not looking to spend $1000.

I have rebuilt a front differential before in my truck, wasn't fun, but i did do it. I would say i have intermediate experience.

Here's a question, Saber are you satisfied with your 3.42s and GURK, would you upgrade to 3.42s if they were an option. Just trying to figure out if i want 3.73s or 3.42s. I don't think 4.10s would be reasonable on my application. Thanks for the responces guys!

What all proper tools are needed to do something of this nature. I used a feeler guage when i did my diff rebuild, but other than that, what else would i need. And what is that paint that is safe to put on the ring to check the pinion's contact patch?

 

Don't buy gears that are made in China. Motive gear is the only one that I can recommend at this time. I also don't like Auburn differentials. I recommend Eaton. Timken bearings are usually best. Do Not use bearings that are made in China.

If you do not expect perfection then using the used gears and differential might be fine. Just understand that it might make a little noise, and may not last as long as new parts. The set up is the important thing. If they are set up correctly then you should have no problems. If they are not set up correctly then you might have some problems, but this goes the same for new parts.

Here are some of the tools that I use. No use for feeler gauges.
http://rides.webshots.com/album/55411986qgnRwr

 

i usually check out randysringandpinion.com because its so useful and the people there are awesome. summit racing also sells ring and pinion sets.

im pretty happy with my 3.23's right now, but if i were to upgrade them, id go up to 3.73's seeing as how id rather have a big gain since id have to go through all the trouble of changing all my bearings aswell.


as for tools youll need a pinion depth gauge, basically a dial indicator with a little contraption that lets it sit where the ring gear would and tells you the pinion depth. also youll probably want an inch pound torque wrench to measure pinion bearing preload.

that yellow stuff your talking about is gear marking compound, they send you a tube and a brush to apply it whenever you buy new gears. its just this gross yellow stuff that gets everywhere. comes in yellow and orange.

also if you decide to swap out your gears yourself id suggest to get a second crush sleeve since its very common for people to over tighten the nut on the flange and go way to high over specification on pinion bearing preload

 

ok, how about if i found someone with a torsen differential with 3.42s. is there anything i should be concerned about. Can someone produce a picture of a torsen differential for me. All the pages with good pictures get red x's in the corner and won't open the image. How do i tell if it is damaged or anything? Anything to watch for? Thanks guys!!!

 

http://www.torsen.com/
http://www.torsen.com/files/Traction...ol_Article.pdf

 

much appreciated!!

 

torsen worm gear differentials are nice and all for the daily driver, but the fact that theres abunch of small worm gears in them doesnt make for a good track car. if you abuse them or race them, youll effin break them. theyre just not made to perform. id go for the clutch pack design posi

 

The best thing for you to do is find a complete rear axle from a 98-02 V8 (LS1) Fbody that had a T56 6 speed transmission. It will have (from the factory) a 3.42 gear and a Zexel Torsen posi unit and disk brakes. You will have to figure out the e-brake but it sounds like you already have that problem or have solved it. I bought one for $260 a year ago and it had 80k miles. Expect to pay anywhere from 200 to 400 and don't pay any more than that.

Swapping out entire rear axles is easier than swapping the gears inside them. It's also much cheaper when you figure out how much it's gonna cost just to have somebody who knows what they are doing properly set up the new gear set and differential in the housing which takes specialized tools and skills. (unless you know how to do this yourself)

 

yea i got a lot of that when i first had the idea, but simply put, within a 200 mile radius, everyone wanted $500 and up for 3.42s/zexel's. I wasn't going to pay that. Found a 2000 3.08/open axle for $100, which matched the gears i had originally so i was happy it matched the speedo for the time being. I also checked for 3.23s, and most of the cars were t-boned, rolled, or side swipped. The axle i ended up finding was 100 miles away, and the front wrapped around a telephone pole, so i knew the axle wasn't tweaked.

I want to learn how to do the rear end properly, and have been studying this for the past 3 months. Watched numerous videos and what not. I know this won't compare to experience, but we all have to learn somewhere.

As far as gears, i found a zexel/3.42 that has 20k on the odometer, so i'm going to see how that looks. Worst case, i found a good website for a eaton, and from there ring/pinion won't be much. Also plan a rebuild of everything on the axle (bearings and what not).

 

like i said the zexel is gonna be a torsen worm gear diff. so it wont handle track duty, but its a good daily driver rear end.

also if you have any problems if you do decide on installing your own gears, give me a pm, ive done it acouple times and had good results.

 

He didn't say anything about it being a track car...and on top of that we're talking about putting behind an L03 what came stock from the factory behind a 350 HP LS1. He shouldn't have to worry about the axle for a long long time. Besides, wouldn't the WCT5 break before the 10 bolt?

84redta: If you're going through the trouble of re-building the whole thing, what about using an axle from a thirdgen car? That way you get the correct length unless you're planning on using aftermarket wheels.

 

well IF he decides he wants it to be a track car, or if he rough houses it too much, that rear end wont last long. the WCT5 would probably break sooner though

 

i've rebuilt the car from the ground up, i've put too much time into this to beat it. It will not be a track car, or have the clutch dropped. I'm planning on doing front LS1 conversion to match the rear LS1 axle, already did booster and all accesories, so brake system is from a 2000, i'm planning on doing a complete suspension rebuild with new poly bushings, new steering system up front, rebuild the axle, already redid the fuel system. Everything on this car is new. I've gone too far to ruin something horsing around.

Thank you gurk, i will probably be asking a few questions as i go along, so your assistance will be greatly appreciated. I don't know if i'm going to pick up this zexel, one of the 10 bolts that holds the ring apparently is stripped, so i don't think that would be terribly hard to deal with, but the main bolt that holds everything inside together is not in or present at all, so i don't know how easy that bolt is to replace, or if that means that all the stuff inside is loose to move around. Don't think i'm going to jump on that deal.

Because i didn't know about the modifications of changing a drum rear to accept LS1 rear brakes at the time, otherwise i would have gone that route. I like the look of the wider rear, and the formula wheels look good with it in my opinion. I'm actually looking for some 3rd gen rear wheel spats to make it look that much more natural. Otherwise i would have rebuild my 3rd gen axle.