rear diff. swap from 96 camaro to 91 firebird
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From: Peoria,Az
Car: 1991 Pontiac Firebird
Engine: Carbed LQ4 6.0
Transmission: blew trans up....T56 on the way
Axle/Gears: 9 bolt 3:45's >:)
rear diff. swap from 96 camaro to 91 firebird
Hey guys I just got a rear disc posi of a 96 camaro 3800 seriesII v6 and im putting it in my 91 firebird. I wanted to know if any one had an idea what kinda power i can put to this rear end? and if i might have any brakeing problems because my rear end right now is drum and swaping it to disc.
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From: oklahoma
Car: 02wrx/88 rs
Engine: 2.0L turbo/nothing yet!
Transmission: 4eat/waiting on a t56
Axle/Gears: 3.73
Re: rear diff. swap from 96 camaro to 91 firebird
im not sure about the power you can get but i do know u will need to switch proportion valve for it. i wanted to put a 87 disk rear in mine but i would have had to change mastercy all the way back. also the forth gen rear is 4inch wider also,
also this post prob should have gone into the susp.
also this post prob should have gone into the susp.
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Junior Member
Joined: Oct 2008
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From: Peoria,Az
Car: 1991 Pontiac Firebird
Engine: Carbed LQ4 6.0
Transmission: blew trans up....T56 on the way
Axle/Gears: 9 bolt 3:45's >:)
Re: rear diff. swap from 96 camaro to 91 firebird
oh sorry I didnt know were to post lol......wait.. the proportion valve?..what exactly is that?
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From: Bastrop, TX
Car: 1988 SC Convertible
Engine: LT-1
Transmission: 700R4
Axle/Gears: 3.23 posi w/PBR's
Re: rear diff. swap from 96 camaro to 91 firebird
Since you have a 91, there's no reason to change the prop valve. My car was originally a drum rear, but I swapped to disk. I never changed the prop valve and everything works great.
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From: Tampa/New Hampshire
Car: 91 camaro RS, 87 T/A
Engine: 350 TBI, 305 TPI
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Axle/Gears: 4th Gen 3.42/BW 3.45
Re: rear diff. swap from 96 camaro to 91 firebird
The prop valves are different, but some people say to change it, and others dont. I Had a pull on mine and i swapped the prop valve and it went away. As for the power, its pretty much the same as a stock 3rd gen 10 bolt.
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From: SF bay area
Car: 86 Camaro iroc-z28
Engine: 305 TPI
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Axle/Gears: 3.42 Posi
Re: rear diff. swap from 96 camaro to 91 firebird
Hey guys I just got a rear disc posi of a 96 camaro 3800 seriesII v6 and im putting it in my 91 firebird. I wanted to know if any one had an idea what kinda power i can put to this rear end? and if i might have any brakeing problems because my rear end right now is drum and swaping it to disc.
96 i believe came with the torsen worm gear differential i believe. which is good for a daily driver, but it wont hold up very well to track duty or any kind of racing, its also 4inches wider, also going from drum to disc, your gonna wanna grab the proportioning valve. its better to be safe than sorry, but sometimes it causes problems such as excessive brake pad wear. so id say just ****** it
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Joined: Oct 2008
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From: Peoria,Az
Car: 1991 Pontiac Firebird
Engine: Carbed LQ4 6.0
Transmission: blew trans up....T56 on the way
Axle/Gears: 9 bolt 3:45's >:)
Re: rear diff. swap from 96 camaro to 91 firebird
cool, thats good to hear....thanks guys..youve been a real good help.
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From: Tampa/New Hampshire
Car: 91 camaro RS, 87 T/A
Engine: 350 TBI, 305 TPI
Transmission: 700r4
Axle/Gears: 4th Gen 3.42/BW 3.45
Re: rear diff. swap from 96 camaro to 91 firebird
Torsen was 98 and up im almost positive. It came out the first year of the LS1 didnt it? and the tires dont stick out too much so dont be alarmed by that.
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From: Naples, FL
Car: 91 RS Camaro, 75 L82 Corvette
Engine: LO3, 383 Stroker
Transmission: 700R4, TH400
Axle/Gears: 4th gen 3.23 posi/LS1 discs, stock
Re: rear diff. swap from 96 camaro to 91 firebird
The 96 rear has the Auburn diff, the one with the clutch packs. And the 96 rear can handle the same power handling capabilities as your stock rear.
There are plenty of threads on this already. look in the Transmisson/Drivetrain section. Or even better, just try searching "4th gen rear swap".
You will also have to change the speedometer gears in the tranny, unless the 4th gen rear is the same gear ratio as the one on your car now.
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From: SF bay area
Car: 86 Camaro iroc-z28
Engine: 305 TPI
Transmission: 700R4
Axle/Gears: 3.42 Posi
Re: rear diff. swap from 96 camaro to 91 firebird
It may work, but your not getting the full stopping power of the rear disk with a disk/drum prop valve. What's the point of swapping in disks if your not gonna use them to there full potential? Do it right and get a disk/disk prop valve. On my 91, when I did a 4th gen rear swap, I bought a 1LE prop valve and used a LS1 master cylinder.
The 96 rear has the Auburn diff, the one with the clutch packs. And the 96 rear can handle the same power handling capabilities as your stock rear.
There are plenty of threads on this already. look in the Transmisson/Drivetrain section. Or even better, just try searching "4th gen rear swap".
You will also have to change the speedometer gears in the tranny, unless the 4th gen rear is the same gear ratio as the one on your car now.
The 96 rear has the Auburn diff, the one with the clutch packs. And the 96 rear can handle the same power handling capabilities as your stock rear.
There are plenty of threads on this already. look in the Transmisson/Drivetrain section. Or even better, just try searching "4th gen rear swap".
You will also have to change the speedometer gears in the tranny, unless the 4th gen rear is the same gear ratio as the one on your car now.
was it till 98 then that the zexel diff came out ?
Thread Starter
Junior Member
Joined: Oct 2008
Posts: 35
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From: Peoria,Az
Car: 1991 Pontiac Firebird
Engine: Carbed LQ4 6.0
Transmission: blew trans up....T56 on the way
Axle/Gears: 9 bolt 3:45's >:)
Re: rear diff. swap from 96 camaro to 91 firebird
I have a buddy that has a 4th gen diff in his 3rd gen camaro...3:73 gears and he didnt swap the valve and he has no breaking problems...unless there is something he hasnt noticet. and you guys say that the 4ths rear handles the same power as my stock one?...i have a stock 5.0 tbi in my bird..and its off a 3800 series..I dont know...i heard there good up to about 200+ horse power but im not too sure....
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From: Tampa/New Hampshire
Car: 91 camaro RS, 87 T/A
Engine: 350 TBI, 305 TPI
Transmission: 700r4
Axle/Gears: 4th Gen 3.42/BW 3.45
Re: rear diff. swap from 96 camaro to 91 firebird
I post up pics all the time of my car for people cause the hardest thing ever is to use the search feature
. But sadly i already posted a pic today and i dont feel like posting again, head over to the driveline forum its about 10 posts down. Thread Starter
Junior Member
Joined: Oct 2008
Posts: 35
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From: Peoria,Az
Car: 1991 Pontiac Firebird
Engine: Carbed LQ4 6.0
Transmission: blew trans up....T56 on the way
Axle/Gears: 9 bolt 3:45's >:)
Re: rear diff. swap from 96 camaro to 91 firebird
here are pictures before and after the rear end went in.


the 4rth gen rear ends do stick out a bit..but i think it gives it a more agressive look.


the 4rth gen rear ends do stick out a bit..but i think it gives it a more agressive look.
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From: Tampa/New Hampshire
Car: 91 camaro RS, 87 T/A
Engine: 350 TBI, 305 TPI
Transmission: 700r4
Axle/Gears: 4th Gen 3.42/BW 3.45
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From: North Carolina
Car: 95 Z28/IROC-Z
Engine: LT1/L98
Transmission: 6 Speed/700R4
Axle/Gears: 3.42/2.77 Boo!
Re: rear diff. swap from 96 camaro to 91 firebird
Has anyone ever cut an inch or so out of the 4th gen rear end before they install it. I'm mean you'd have to get new axles that are the correct length, but if the width is a problem that should solve it. Depends on how much axles are though I guess.
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From: Sacramento
Car: 91 RS
Engine: 350 TBI
Transmission: WC T5
Axle/Gears: 3.42 Posi
Re: rear diff. swap from 96 camaro to 91 firebird
Am I the only one that's fairly certain that any rear end from a V6 camaro doesn't have a posi at all?? Not sure why you guys are all talking about Torsens and whatnot.
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From: North Carolina
Car: 95 Z28/IROC-Z
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Axle/Gears: 3.42/2.77 Boo!
Re: rear diff. swap from 96 camaro to 91 firebird
Double Post
Last edited by Calaban007; Feb 16, 2009 at 02:46 PM.
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From: North Carolina
Car: 95 Z28/IROC-Z
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Transmission: 6 Speed/700R4
Axle/Gears: 3.42/2.77 Boo!
Re: rear diff. swap from 96 camaro to 91 firebird
There were some 4th gens with the 3800 that had a performance package, Y87, I believe was the RPO code. The had positive rear ends. I don't know how many were made though.
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From: Bertram (outside Austin), TX
Car: 87 GTA
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Re: rear diff. swap from 96 camaro to 91 firebird
The tires will still under under the outermost portion of the fender lip. Not end up like reverse offset, spoked lowrider wheels.
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