3rd/4th gen rear axles
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Car: 80 SE/TTA;88 T/A GTA;86 T/A
Engine: 4.9L Turbo; LT1; empty
Transmission: TH350; T56; empty
Axle/Gears: 3:23 disk; 4:10 disk ; 3.42 disk
3rd/4th gen rear axles
I've done the research so this is just kinda of a cap off of it and a couple last questions. I'm looking into a 99 rear axle, which correct me if i'm wrong i will just need the ebrake cable assembly for other than the complete rear axle. I'm picking up the brake booster/master cylinder/proportioning valve as the 98+ booster and accesories bolt right up so that i can also do my drum to disk swap. The car i'm getting it from has 3.08's so i'm not terribly worried about it as my bird has 3.08s so for right now i don't have to play with the speedo so thats good. The doner car is low miles, and has a really nice set of PBR rear disk brakes with brand new pads. In the future though i do plan on getting a set of ring and pinion gears plus an LSD from a doner car and/or purchase new if my pockets somehow become swollen with cash.
Anyways, i'm looking up new ring and pinion sets now online and they are speaking of 10 bolt...82-02 for camaro and firebird. It also included many years of s10/s15, and similar trucks (jimmy/sonoma/blazer) along with many of the full size RWD cars, like buicks and such. Can i assume that i can get ring and pinion gears along with an LSD from a 3rd/4th gen or other vehicles if the 99 axle is a 10 bolt????? This would be great news to me as i'm sure i can find a doner car or someone on here can hook me up with the ring and pinion gears but if i can get them locally obviously they would be cheaper.
I guess what i'm asking is a complete list of compatable vehicles with acceptable ring and pinion gears for a said 99 V6 Automatic rear axle (NON y87 performance package) and if any of the information i've gathered may be wrong as i'm not completely experienced obviously and i'd like to hear from experiences of other people. Thanks!
Jon
Anyways, i'm looking up new ring and pinion sets now online and they are speaking of 10 bolt...82-02 for camaro and firebird. It also included many years of s10/s15, and similar trucks (jimmy/sonoma/blazer) along with many of the full size RWD cars, like buicks and such. Can i assume that i can get ring and pinion gears along with an LSD from a 3rd/4th gen or other vehicles if the 99 axle is a 10 bolt????? This would be great news to me as i'm sure i can find a doner car or someone on here can hook me up with the ring and pinion gears but if i can get them locally obviously they would be cheaper.
I guess what i'm asking is a complete list of compatable vehicles with acceptable ring and pinion gears for a said 99 V6 Automatic rear axle (NON y87 performance package) and if any of the information i've gathered may be wrong as i'm not completely experienced obviously and i'd like to hear from experiences of other people. Thanks!
Jon
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Car: 1991 Z28 1LE
Engine: LS1
Transmission: T56
Axle/Gears: 3.42
Re: 3rd/4th gen rear axles
What gear ratio do you eventually want to go with? If not lower that 3.42 I would just get a rear out of an LS1 car with the ratio you're looking to someday get. It will be much cheaper.
If you still decide to go this route you just need to get a carrier for a 7.5" / 7.625" with the correct spline count for your axles.
If you still decide to go this route you just need to get a carrier for a 7.5" / 7.625" with the correct spline count for your axles.
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Car: 80 SE/TTA;88 T/A GTA;86 T/A
Engine: 4.9L Turbo; LT1; empty
Transmission: TH350; T56; empty
Axle/Gears: 3:23 disk; 4:10 disk ; 3.42 disk
Re: 3rd/4th gen rear axles
i looked up an ls1 rear axle and people around me are trying for $400 - $700...i can get this rear axle for $125, and then find out of another axle the ring and pinion for $50 (or just take it all apart there, put it back together and just pay the $125 for everything i want)...so less than $200 is good to me. Unless someone in NY can hook me up with something that cheap i don't have the money. And at this point it's got the same 3.08 as me already but with PBR disks...so even if i take 3 years to go out and get gears i don't need to tinker with the speedo.
and i ask if it's the same 10 bolt setup 3rd to 4th cause i got like 6 3rd gens available to me, and at least 3 or 4 z28s or t/a's so i'm assuming out of them i should be able to find a decent gear set and LSD.
I would like the 3.42/LSD package they got with the performance package of those years. I'm assuming they used the same axle assembly...just changed the ring and gearing. Correct me if i'm wrong. I got 3.23's sitting in my other garage i kno would b a direct swap for the axle i have at the moment but i figure if im going to do all this work i want something more gear/brake wise and a lsd.
Ok so i pop the back off the axles....what am i counting as far as splines??? and what are you refering to with carriers. I've done the research and read this but it's used lightly and the people that talked about it, understood it...i don't. If you can explain what i'm measuring for the 7.5"/7.625 carrier (i'm assuming the housing??) and the spline count (where do i look on my car to understand what i need?) I thank you for your time!
Jon
and i ask if it's the same 10 bolt setup 3rd to 4th cause i got like 6 3rd gens available to me, and at least 3 or 4 z28s or t/a's so i'm assuming out of them i should be able to find a decent gear set and LSD.
I would like the 3.42/LSD package they got with the performance package of those years. I'm assuming they used the same axle assembly...just changed the ring and gearing. Correct me if i'm wrong. I got 3.23's sitting in my other garage i kno would b a direct swap for the axle i have at the moment but i figure if im going to do all this work i want something more gear/brake wise and a lsd.
Ok so i pop the back off the axles....what am i counting as far as splines??? and what are you refering to with carriers. I've done the research and read this but it's used lightly and the people that talked about it, understood it...i don't. If you can explain what i'm measuring for the 7.5"/7.625 carrier (i'm assuming the housing??) and the spline count (where do i look on my car to understand what i need?) I thank you for your time!
Jon
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Car: 1991 Z28 1LE
Engine: LS1
Transmission: T56
Axle/Gears: 3.42
Re: 3rd/4th gen rear axles
The carrier is the part that the ring gear bolts to and the axles attach to, and is the part that makes it an open rear or a posi rear. The splines are on the axles, and some carriers use 26 splines and some use 28. I'm 99% sure that all 4th gen rears are 28 count.
So if you were going to use the donor 3rd gen rears you have around, you'll just need a carrier that will take the 28 spline axles from the 4th gen rear.
Hope this helps, Kenny.
So if you were going to use the donor 3rd gen rears you have around, you'll just need a carrier that will take the 28 spline axles from the 4th gen rear.
Hope this helps, Kenny.
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Car: 80 SE/TTA;88 T/A GTA;86 T/A
Engine: 4.9L Turbo; LT1; empty
Transmission: TH350; T56; empty
Axle/Gears: 3:23 disk; 4:10 disk ; 3.42 disk
Re: 3rd/4th gen rear axles
is there a lot of work to doing a gear swap...i was just sitting back doing a little research...the axle swap from a 4th gen poses it's own problems to deal with and fabricate methods of working...not a real big problem, but i'm reading a thread that is fresh talking about switching to posi and it's talking about how hard it is and what not. I have a bit of experience with axle...although more so with the Independant suspension systems, but i've had to replace axle shafts in the differentials before...and it seems similar in this sense as i'm doing the research, you pull the axles out and install the LSD/gears and put the axle shafts back in, space it all out and tighten all the bolts to specs. Am i over simplifying this??? Cause i started thinking of the probs with doing the 4th gen swap so i thought about swaping gears and lsd into what i got and keeping the drums for right now, but even that seems as thought it's going to be a difficult thing. I don't know what i should ultimately do.
my options are i know at one JY there is an 88 Automatic T/A with drums...but i assume it has higher gears and an LSD, i know there is like an 84 t/a and and 2 84 z28s...so i'm assuming out of the three ultimately i could find one gear/lsd package i like...but what do i look for??? How do i tell that the LSD is working w/out driving the car, and how do i tell when i shouldn't even bother pulling gears (obviously open up the backs but what do i look at after that)? Is there a source (as i haven't found one yet) that explains the number of splines on the ring gear per the specific gear ratio?
My other option is the 4th gen rear and wait for someone to gut a 4th gen auto v6 with the Y87 3.42/lsd package. I know the install isn't going to be a piece of cake on the axle itself...but then is the gears going to be difficult to swap, space, install, ect??? What pertains to the LSD/gear/rebuild kits i see on ebay and all over for $600...is that what i'm ultimately going to be spending when i go to do this gear swap. Is the rebuild necessary reguardless??
I'm sorry i know i'm all over with these questions...but at this point your opinion is probably going to guide me to what i should do. All in all...full time college student, limited to funds...not looking for a drag car and only dealing with a stock LO3 for now, what would you do? I see with all this drama why people go straight for the exact axle they want...but i'm trying to play around with what i have available to me to see on my budget what i can get the most out of w/out skimping on quality of the output. Thank you for being so descriptive and responsive!!!
my options are i know at one JY there is an 88 Automatic T/A with drums...but i assume it has higher gears and an LSD, i know there is like an 84 t/a and and 2 84 z28s...so i'm assuming out of the three ultimately i could find one gear/lsd package i like...but what do i look for??? How do i tell that the LSD is working w/out driving the car, and how do i tell when i shouldn't even bother pulling gears (obviously open up the backs but what do i look at after that)? Is there a source (as i haven't found one yet) that explains the number of splines on the ring gear per the specific gear ratio?
My other option is the 4th gen rear and wait for someone to gut a 4th gen auto v6 with the Y87 3.42/lsd package. I know the install isn't going to be a piece of cake on the axle itself...but then is the gears going to be difficult to swap, space, install, ect??? What pertains to the LSD/gear/rebuild kits i see on ebay and all over for $600...is that what i'm ultimately going to be spending when i go to do this gear swap. Is the rebuild necessary reguardless??
I'm sorry i know i'm all over with these questions...but at this point your opinion is probably going to guide me to what i should do. All in all...full time college student, limited to funds...not looking for a drag car and only dealing with a stock LO3 for now, what would you do? I see with all this drama why people go straight for the exact axle they want...but i'm trying to play around with what i have available to me to see on my budget what i can get the most out of w/out skimping on quality of the output. Thank you for being so descriptive and responsive!!!
Last edited by 84redta; 02-05-2008 at 03:03 PM.
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Car: 1991 Z28 1LE
Engine: LS1
Transmission: T56
Axle/Gears: 3.42
Re: 3rd/4th gen rear axles
Well lets see, with the 4th gen rear there is no fabrication needed except for the e-brake cables, everything else bolts exactly the same as the 3rd gen rear. Also for the 4th gen rear make sure the one you get has 3 channel brakes and NOT 4 channel brakes, meaning get the one without traction control. Theres a post somewhere called "thinking 4th gen rear swap" with a great deal of information.
As far as putting the gears in yourself, I've never done it before, but those are basically all the steps just use marking compound so you know when the gears are making full contact. When I got my 4th gen rear it had 3.23's in it and I wanted to put in my 4.11's but every shop around me wanted around $500 to do it, so I asked around and found a guy who did freelance work in his spare time and he did it for me for $125 and in less than a day, which is incredibly fast for someone on there own time.
You can test the rear before hand by raising the rear of the car and turning the wheels by hand and if they both move in the same direction then it is posi, if they turn in different directions then it is open. I read a while back that when a posi is bad it will still turn both wheels but if you have another person on the other wheel and they hold it while you turn the wheel and it takes more than like 30lbs of force to move it then it is still good, something like that.
I believe the way to check the gear ratio without pulling the cover off is:
mark on the bottom of the driveshaft with chalk and mark on the top of the tire, and then turn the tire one revolution and count how many times the driveshaft turns. Such as an even 3 turns of the driveshaft would be 3.08 or 3 and a half turns would be 3.42 and so on.
As far as splines, they aren't on the ring gear just the axles and inside the carrier. What I've read is I think in 86 or 87 is when GM went from 26 spline axles to 28 spline, I'm not sure if they still used 26 spline setups still or not.
I don't know what rebuild kits your refering to but I definately wouldn't bother with them, if you want to use all new bearings and bolts inside the rear then just get a complete instal kit from Ratech or Moser there around the $100 dollar range. A rebuild is not neccessary, with my rear I got it from the jy took it to that guys house used the same carrier he said everything looked good inside and threw it on my car.
Based on what your saying that your not looking for a drag car and you have limited funds I think I would wait until I found the rear I was looking for with the brakes that I wanted and the gear ratio I was looking for just my
Kenny.
As far as putting the gears in yourself, I've never done it before, but those are basically all the steps just use marking compound so you know when the gears are making full contact. When I got my 4th gen rear it had 3.23's in it and I wanted to put in my 4.11's but every shop around me wanted around $500 to do it, so I asked around and found a guy who did freelance work in his spare time and he did it for me for $125 and in less than a day, which is incredibly fast for someone on there own time.
You can test the rear before hand by raising the rear of the car and turning the wheels by hand and if they both move in the same direction then it is posi, if they turn in different directions then it is open. I read a while back that when a posi is bad it will still turn both wheels but if you have another person on the other wheel and they hold it while you turn the wheel and it takes more than like 30lbs of force to move it then it is still good, something like that.
I believe the way to check the gear ratio without pulling the cover off is:
mark on the bottom of the driveshaft with chalk and mark on the top of the tire, and then turn the tire one revolution and count how many times the driveshaft turns. Such as an even 3 turns of the driveshaft would be 3.08 or 3 and a half turns would be 3.42 and so on.
As far as splines, they aren't on the ring gear just the axles and inside the carrier. What I've read is I think in 86 or 87 is when GM went from 26 spline axles to 28 spline, I'm not sure if they still used 26 spline setups still or not.
I don't know what rebuild kits your refering to but I definately wouldn't bother with them, if you want to use all new bearings and bolts inside the rear then just get a complete instal kit from Ratech or Moser there around the $100 dollar range. A rebuild is not neccessary, with my rear I got it from the jy took it to that guys house used the same carrier he said everything looked good inside and threw it on my car.
Based on what your saying that your not looking for a drag car and you have limited funds I think I would wait until I found the rear I was looking for with the brakes that I wanted and the gear ratio I was looking for just my
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Kenny.
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Car: 80 SE/TTA;88 T/A GTA;86 T/A
Engine: 4.9L Turbo; LT1; empty
Transmission: TH350; T56; empty
Axle/Gears: 3:23 disk; 4:10 disk ; 3.42 disk
Re: 3rd/4th gen rear axles
thank you very much...thats where i was leading towards but i just needed someone elses opinion on it. The "thinking 4th gen rear swap" is me i beleive, lol. I was also informed that the 3/4 channel issue was simply fixed by a t-brake splitter. I think i'm going to wait on spending money on a 4th gen rear as thats what i ultimately want as i'm not going to want to spend that much money on something that is already 20+ years old...i like <10 years a lot better...on the other hand my camaro that i have in my shop has 3.23's...from a 3.08 am i going to notice anything??? Would it be worth it for now? I mean now with the 3.08 i feel the torque, it puts you against the seat, but will 3.23 net anything obvious or benefitial???
Also in the future I'm worried 3.42s or 3.73s are going to screw up my 5th gear cruising as i would be using this car frequently for highway driving and i need a decent amoung of gas consumption (i know an oximoron owning a v8 car but). I just like where it sits now on the tach in 5th gear now...is 3.42/3.73 gonna jump it close or above 2000 RMPs??
I thank you for being so complete and informative...it's really helping.
Also in the future I'm worried 3.42s or 3.73s are going to screw up my 5th gear cruising as i would be using this car frequently for highway driving and i need a decent amoung of gas consumption (i know an oximoron owning a v8 car but). I just like where it sits now on the tach in 5th gear now...is 3.42/3.73 gonna jump it close or above 2000 RMPs??
I thank you for being so complete and informative...it's really helping.
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Car: 1991 Z28 1LE
Engine: LS1
Transmission: T56
Axle/Gears: 3.42
Re: 3rd/4th gen rear axles
No problem I aint got too much going on, just waiting for all my stuff to get to Europe. Yes with the 4 channel 4th gen rears they can easily be changed back to 3 channel with a T-block and new lines.
You really wouldn't notice too much a difference going from 3.08 to 3.23, it would be maybe 2 tenths of a second in a 1/4 mile maybe less.
There are some calculators to see what RPMs you'll do with certain rear ratios on other sites I think iroczone.com has some.
You really wouldn't notice too much a difference going from 3.08 to 3.23, it would be maybe 2 tenths of a second in a 1/4 mile maybe less.
There are some calculators to see what RPMs you'll do with certain rear ratios on other sites I think iroczone.com has some.
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Car: 80 SE/TTA;88 T/A GTA;86 T/A
Engine: 4.9L Turbo; LT1; empty
Transmission: TH350; T56; empty
Axle/Gears: 3:23 disk; 4:10 disk ; 3.42 disk
Re: 3rd/4th gen rear axles
ok, i'll check that out but do you think that performance wise i would notice that i spent countless hours getting rusty nasty bolts out of both cars to do this 3.08/3.23 swap? The only reason i thought about doing this is that i have to take all but the LCA bolts out to drop the axle to do a fuel pump swap so i figured while i was down there i might do something but if it isn't going to be worth it i'll just make the fuel pump swap as simple as possible.
And just curious, were f-bodies shipped to Germany regularly or did they have to be shipped in by you or another consumer?
And just curious, were f-bodies shipped to Germany regularly or did they have to be shipped in by you or another consumer?
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Car: 80 SE/TTA;88 T/A GTA;86 T/A
Engine: 4.9L Turbo; LT1; empty
Transmission: TH350; T56; empty
Axle/Gears: 3:23 disk; 4:10 disk ; 3.42 disk
Re: 3rd/4th gen rear axles
and as far as the 3.23 axle, it's an 84 from my profile and my only other concern is that i heard in '88 is when they made the full switch to 28 spline as the 26 wasn't terribly durable...so thats what makes me worry about using the 84 cause i know it's almost guaranteed 26 spline.
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Car: 1991 Z28 1LE
Engine: LS1
Transmission: T56
Axle/Gears: 3.42
Re: 3rd/4th gen rear axles
If the 3.23 rear is a posi I would consider doing it, but if it is also open I wouldn't waste my time. There isn't a huge difference in durability between 26 and 28 spline axles, you don't have anything to worry about with a stock Lo3
I was stationed in Germany a few years ago with the army and I just got out and me and the wife wanted to live here again for a little while as a civilian. So when I got out last month we told them to ship all our household items to Germany and now I'm just waiting for customs to release my car and I'll go pick it up.
I was stationed in Germany a few years ago with the army and I just got out and me and the wife wanted to live here again for a little while as a civilian. So when I got out last month we told them to ship all our household items to Germany and now I'm just waiting for customs to release my car and I'll go pick it up.
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Car: 80 SE/TTA;88 T/A GTA;86 T/A
Engine: 4.9L Turbo; LT1; empty
Transmission: TH350; T56; empty
Axle/Gears: 3:23 disk; 4:10 disk ; 3.42 disk
Re: 3rd/4th gen rear axles
thats cool, yea my father was stationed in germany in the air force and i remember all the stories about having US cars brought thru customs and all. I didn't think i would have much to worry about with the LO3, but i thought the gearing might spike it a little. I'm not going to bother doing the swap cause it's just another open 3.23. I'm just going to cut my losses and wait till i can get a hold of a 4th gen axle i like. I thank you for your time and all the knowledge you've passed to me. Thanks again!
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Car: 1991 Z28 1LE
Engine: LS1
Transmission: T56
Axle/Gears: 3.42
Re: 3rd/4th gen rear axles
Sure, no problem. You might want to check out ebay for a 4th gen rear, that's where I got mine from, from "Cleveland pick'a part", and I was very happy with price, and shipping. All the jy around me wanted $600+ for a 2.73 rear, and I picked the one from ebay for $485 shipped to Maryland (LS1 rear w/ 3.23) plus I was able to sell my old 9 bolt for $150. Also thought I would mention that the only thing I had to do with the LS1 e-brake cables was use some rope clamps to shorten the passenger one and they work fine that way.
Good luck with everything, Kenny
Good luck with everything, Kenny
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