Now Ring Gear Confusion!

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Sep 11, 2008 | 12:14 PM

Hello, Michael

Thread Starter

Member

Joined: May 2008

Posts: 286

Likes: 1

From: Cicero, IL.

Car: 1987 Pontiac Firebird Trans Am WS6

Engine: SBC 350

Transmission: T-56

Axle/Gears: 3.70:1 BW M78 9-Bolt Posi

Now Ring Gear Confusion!

My 87 Trans Am has a 2.77 axle ratio. I'm hearing that this is a 9-Bolt carrier (Series 2). I'm planning on ordering a 3.73 gear set, but I don't see anything on Jegs about a 9-Bolt. I see the gear set for the Series 2 carrier and Series 3 carrier. It states that Series 2 is 3.08 and lower carrier, and Series 3 is 3.23 and higer carrier. So, do i have a 9 or 10 bolt carrier?!!

Sep 11, 2008 | 12:23 PM

JamesC

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iTrader: (5)

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

Re: Now Ring Gear Confusion!

Quote:

Originally Posted by Hello, Michael

So, do i have a 9 or 10 bolt carrier?!!

Crawl under the car and count the bolts. Should you have a 9-bolt, finding parts may be difficult. Check the following link for a ton of info:

https://www.thirdgen.org/forums/faq-...now-about.html

JamesC

Last edited by JamesC; Sep 11, 2008 at 12:28 PM.

Sep 11, 2008 | 01:56 PM

DJP87Z28

Supreme Member

Joined: Mar 2003

Posts: 4,771

Likes: 15

From: Florida

Car: 1987 Black IROC-Z (SOLD)

Re: Now Ring Gear Confusion!

2:77 gear ratio is from a BW 9-bolt rear and you will find very few replacement parts. Most everything from a Autoparts suppliers are for 10-bolts and the part are NOT interchangeable. Example: 9-bolt ring gear 7.750 dia vs 10-bolt ring gear 7.5/.625 dia.