1991 9-Bolt Rear End
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From: Northern Kentucky
Car: 1991 Trans Am GTA, 2003 Grand Am GT
Engine: 350 Tune Port
Transmission: 700R4
1991 9-Bolt Rear End
I have a 91' GTA that I am totally restoring. The new engine will have about 350 HP and I am relatively sure that it is going to need rebuilt. I think I only have the 2.77 gears as well. Is this something that I can do myself with some general knowledge? I have never rebuilt the rear end of a car, so this would be new. Also, where can I find 3.42 gearing and a rebuild kit for the 9-bolt?
Thanks for your help!
Thanks for your help!
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Joined: Feb 2000
Posts: 7,015
Likes: 2
From: Schererville , IN
Car: 91 GTA, 91 Formula, 89 TTA
Engine: all 225+ RWHP
Transmission: all OD
Axle/Gears: Always the good ones
If its 91 and original, it wont have a 9 bolt. An early 90 might, but not a 91, least that I have evr seen or heard verified.
Do a search for 9 bolt gears and they should net yuou 3-4 places.
later
Jeremy
Do a search for 9 bolt gears and they should net yuou 3-4 places.
later
Jeremy
Joined: Aug 1999
Posts: 19,282
Likes: 103
From: Lawrence, KS
Car: Met. Silver 85 IROC/Sold
Engine: 350 HO Deluxe (350ci/330hp)
Transmission: T-5 (Non-WC)
Axle/Gears: Limited Slip 3.23's
Originally Posted by wildjyoung
Is this something that I can do myself with some general knowledge?
JamesS
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From: Northern Kentucky
Car: 1991 Trans Am GTA, 2003 Grand Am GT
Engine: 350 Tune Port
Transmission: 700R4
Rear End
I will have to double check the rear end to verify that it is in fact a 9-bolt. It is the original. What is the best way to identify if it is a 9-bolt or 10-bolt?
Thanks for everyones help!
Thanks for everyones help!
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From: Orland Park, IL
Car: 1984 Z28
Engine: SLOW carbed ls
Transmission: TH400 with brake, 8" PTC converter
Axle/Gears: moser 9" 4.11
rubber plug on the back cover is a 9 bolt. or count the bolts....if your math adds up to 10 bolts then you have a ten bolt, but if for some reason you keep counting over and over and only get to 9 bolts, then you have a 9 bolt rear end. 
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From: Baton Rouge, LA
Car: 89 RS
Engine: 305
Transmission: th350
Originally Posted by xpndbl3
rubber plug on the back cover is a 9 bolt. or count the bolts....if your math adds up to 10 bolts then you have a ten bolt, but if for some reason you keep counting over and over and only get to 9 bolts, then you have a 9 bolt rear end.
Its funny you mention that. I told a friend that and he counted 9. I dident think anything of it and was to lazy to crawl down there and count. A few weeks later i was taking the driveshaft out of the car and decided to look and he was missing a bolt in the cover.
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iTrader: (5)
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From: Orland Park, IL
Car: 1984 Z28
Engine: SLOW carbed ls
Transmission: TH400 with brake, 8" PTC converter
Axle/Gears: moser 9" 4.11
well there's no such thing as stupid questions, just stupid people.
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Joined: Jan 2003
Posts: 77
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From: Michigan
Car: 1992 Chevrolet Camaro RS
Engine: 5.0L (305ci) TBI V8
Transmission: 4-Speed Automatic O/D
Axle/Gears: 9-bolt Borg Warner, 3.70 posi
Originally Posted by Necro
Its funny you mention that. I told a friend that and he counted 9. I dident think anything of it and was to lazy to crawl down there and count. A few weeks later i was taking the driveshaft out of the car and decided to look and he was missing a bolt in the cover.
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Joined: Sep 2000
Posts: 1,940
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From: Glendale, AZ
Car: 4 Mopars total
Engine: Pentastar power
Transmission: T/F and New Process
Axle/Gears: Three 8 3/4's & one 9 1/4
Member
Joined: Jan 2006
Posts: 355
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From: Central California Coast SM
Car: 91 Z28 24th Anniversary
Engine: L98
Transmission: Auto
Axle/Gears: Posi 3.23
Is the rubber plug on the cover a deciding factor for a 9 bolt? What are the other exterior differences? I have a friend who says he has an 82 CFI Z with rear discs and says it's a 9 bolt. He also states they only put them in for a couple months. He bought it new and ordered it. I talked to him today and I asked him if I could take pictures of it. If it is a 9 bolt I will take pics. Just need some obvious differences for the photos.
Joined: Aug 1999
Posts: 19,282
Likes: 103
From: Lawrence, KS
Car: Met. Silver 85 IROC/Sold
Engine: 350 HO Deluxe (350ci/330hp)
Transmission: T-5 (Non-WC)
Axle/Gears: Limited Slip 3.23's
Member
Joined: Jan 2006
Posts: 355
Likes: 2
From: Central California Coast SM
Car: 91 Z28 24th Anniversary
Engine: L98
Transmission: Auto
Axle/Gears: Posi 3.23
This guy bought the car new. It might have 12,000 miles on it, although he painted it around 1992. Why, 'cause he wanted to. I'll check on it and get back.
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