87 firebird with posi?
Thread Starter
Supreme Member
iTrader: (2)
Joined: Sep 2003
Posts: 10,494
Likes: 3
From: Woodland, CA
Car: '02 Z06
Engine: L33 5.7
Transmission: T56
Axle/Gears: Stock IRS
87 firebird with posi?
my supervisor's husband at work has a 87 v6 firebird, its been wrapped around a truck, and sitting in his yard for about 3 years now. whats the chances this v6 firebird had posi? cuz if so, i know they will just let me strip it form the car. it sure as hell would beat me 3.08 posi. but i only would want this new rearend if its posi as well.
whats the chances? i cant call them yet cuz they still at work.
whats the chances? i cant call them yet cuz they still at work.
Joined: Mar 2000
Posts: 43,187
Likes: 43
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
It probably has 3.42 gears.
The likelihood of it being posi is very slim. However, it is possible.
It should be worth it for the gears alone. But, it would also be 26 spline.
Whatever...
The likelihood of it being posi is very slim. However, it is possible.
It should be worth it for the gears alone. But, it would also be 26 spline.
Whatever...
Joined: Mar 2000
Posts: 43,187
Likes: 43
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Your '89 may be 26-spline as well.
I'd take the whole rear if possible. Swap it all in. If it isn't posi, get a PowerTrax for it.
I'd take the whole rear if possible. Swap it all in. If it isn't posi, get a PowerTrax for it.
Supreme Member

Joined: Jan 2002
Posts: 3,852
Likes: 1
From: Valley of the Sun
Car: 82 Z28
Engine: Al LT1 headed LG4 305
Transmission: TH350
Axle/Gears: 3.73 posi with spacer
I don't think V6 cars came with posi.
Powertrax Lock-Right Lockers
Powertrax No-Slip Traction Systems
Summit Racing Equipment - Differential Carriers
Powertrax Lock-Right Lockers
Powertrax No-Slip Traction Systems
Summit Racing Equipment - Differential Carriers
Supreme Member
Joined: Sep 2001
Posts: 6,111
Likes: 53
From: Ontario, Canada
Car: 1988 Firebird S/E
Engine: 406Ci Vortec SBC
Transmission: TH-350/3500stall
Axle/Gears: 7.5" Auburn 4.10 Posi-Traction
Not likely a posi on a V6 car. But it is a option.
Open the center console and look at the option codes.
Find G80 for limited slip axle and GU4 for 3.23 and GU5 for 3.42. most likely 3.42:1. If it is a posi you'll probabily want to ****** the axles too. '87= 26 spline. your '89 likely 28 spline.
Open the center console and look at the option codes.
Find G80 for limited slip axle and GU4 for 3.23 and GU5 for 3.42. most likely 3.42:1. If it is a posi you'll probabily want to ****** the axles too. '87= 26 spline. your '89 likely 28 spline.
Trending Topics
Joined: Mar 2000
Posts: 43,187
Likes: 43
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Why not just get the whole rear?
If it's open, get a PowerTrax for 28-spline, put it along with your axles in the '87 rear, now you've got a 3.42 "posi" with 28-spline axles.
If it's open, get a PowerTrax for 28-spline, put it along with your axles in the '87 rear, now you've got a 3.42 "posi" with 28-spline axles.
Thread Starter
Supreme Member
iTrader: (2)
Joined: Sep 2003
Posts: 10,494
Likes: 3
From: Woodland, CA
Car: '02 Z06
Engine: L33 5.7
Transmission: T56
Axle/Gears: Stock IRS
how much would this run me ?i got to talk to the guy, its confirmed not posi.
keep in mind my current rearend is already posi. would it be cheaper to just buy gears for my current rearend?
also, he said the 5speed in it is great shape.
is their any market for t-5's that were attached to a v6?
keep in mind my current rearend is already posi. would it be cheaper to just buy gears for my current rearend?
also, he said the 5speed in it is great shape.
is their any market for t-5's that were attached to a v6?
Supreme Member

Joined: Jan 2002
Posts: 3,852
Likes: 1
From: Valley of the Sun
Car: 82 Z28
Engine: Al LT1 headed LG4 305
Transmission: TH350
Axle/Gears: 3.73 posi with spacer
The V6 t-5 are junk way worse then the v8 ones. Also they do not bolt up, you have to change the bellhousing to the v8 pattern.
Senior Member

Joined: May 2001
Posts: 699
Likes: 1
From: Houston TX
Car: 84 Z-28 Camaro, 2022 2500 silverado
Engine: 383
Transmission: T-56
Axle/Gears: richmond 3.73, eaton posi
oh well, I guess I'll keep saving for that T56, I have about $1,000 saved now the web siter I was looking at wants ~$2000 for one.
Joined: Mar 2000
Posts: 43,187
Likes: 43
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
You have 3.08 posi, 28-spline.
The other car has 3.42 open, 26 spline.
The 3.42's won't fit your 2-series posi carrier. I suppose you could go with a ring gear spacer. You'd have to have a shop set the gears up (this isn't something you want to try without the proper equipment, which typically costs more than the set-up labor). Probably cost you in the neighborhood of $275-$400 total.
Putting the other rear in with a PowerTrax and your axles would cost you about $325 for the PowerTrax plus whatever he wants for the rear (probably not worth more than $75-$100).
Might as well have a shop install 3.42 gears for 2-series carrier in your current rear. Probably run in the neighborhood of $300-$450 total.
The other car has 3.42 open, 26 spline.
The 3.42's won't fit your 2-series posi carrier. I suppose you could go with a ring gear spacer. You'd have to have a shop set the gears up (this isn't something you want to try without the proper equipment, which typically costs more than the set-up labor). Probably cost you in the neighborhood of $275-$400 total.
Putting the other rear in with a PowerTrax and your axles would cost you about $325 for the PowerTrax plus whatever he wants for the rear (probably not worth more than $75-$100).
Might as well have a shop install 3.42 gears for 2-series carrier in your current rear. Probably run in the neighborhood of $300-$450 total.
Thread Starter
Supreme Member
iTrader: (2)
Joined: Sep 2003
Posts: 10,494
Likes: 3
From: Woodland, CA
Car: '02 Z06
Engine: L33 5.7
Transmission: T56
Axle/Gears: Stock IRS
or couldnt i just buy high gears for my rear end and have them installed?
http://store.summitracing.com/partde...=RMG%2D4900071
3.73 for a 2-series 28 spline.
http://store.summitracing.com/partde...=RMG%2D4900071
3.73 for a 2-series 28 spline.
Joined: Mar 2000
Posts: 43,187
Likes: 43
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
That's the concept.
I thought/assumed 3.42's were what you wanted.
I thought/assumed 3.42's were what you wanted.
Thread Starter
Supreme Member
iTrader: (2)
Joined: Sep 2003
Posts: 10,494
Likes: 3
From: Woodland, CA
Car: '02 Z06
Engine: L33 5.7
Transmission: T56
Axle/Gears: Stock IRS
well i would really take anything, just 3.42 were on the car and better then what i currently have.
Member
Joined: Jun 2002
Posts: 344
Likes: 0
From: Vermont
Car: 1986 W69 Special Edition
Engine: 2.8/ECM/Int/Exh
Transmission: T5
Axle/Gears: 3.42 posi
Originally posted by ME Leigh
I don't think V6 cars came with posi.
I don't think V6 cars came with posi.
Thread
Thread Starter
Forum
Replies
Last Post
hectre13
Engine/Drivetrain/Suspension Parts for Sale
2
Dec 11, 2023 08:14 AM
1992 Trans Am
History / Originality
27
May 10, 2023 07:19 PM
hectre13
Engine/Drivetrain/Suspension Parts for Sale
7
Aug 26, 2015 08:17 AM
Dialed_In
Firebirds for Sale
2
Aug 20, 2015 01:45 PM






