possi differential unit - Team Camaro Tech
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post #1 of 7 (permalink) Old Jan 10th, 01, 03:16 PM Thread Starter
Join Date: Dec 2000
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I just bought a 12 bolt rear end for a 69 camaro but, the rear end is pretty beat up! The possi unit inside or 3rd member or what ever you call the thing that carrys the spider gears and clutches is broken. It has a hole in it and the gears are stripped like if the rear end was used for the drags or racing. Do you know anybody or any store that sells this part without costing an arm and a leg? Please help! Too much money wasted on the 12 bolt unit.Thanks!
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post #2 of 7 (permalink) Old Jan 10th, 01, 04:17 PM
David Pozzi
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Location: Central California, USA
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If it's just the spider gears that are bad you can replace them and the center pin. They come in a kit.
If you have other stuff wrong, you can buy a new Eaton limited slip unit.
Most of the gear vendors with adds at the back of the car magazines sell them.
Stay away from the cone type Auburn units, they don't last as long.
Make sure everything else is OK too.
Check the gears for wear and excessive backlash or damage.
Check the bearings and look at the axles real close, also look at where the axle bearings ride on the axles for pitting.
I'm going to have an extra set of spider gears to sell as I'm replacing the ones in a 12 bolt I just bought. I'm going to 33 spline axles and a slightly narrowed rear.
If you get a whole new unit, you'll get the new spider gears.

Check my web page for First Gen Camaro suspension info:
David's Motorsports page
First Gen Suspension Page
67 RS 327
69 Camaro Vintage Racer
65 Lola T-70 Can Am Vintage Racer

[This message has been edited by davidpozzi (edited 01-10-2001).]
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post #3 of 7 (permalink) Old Jan 10th, 01, 04:19 PM
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What you are describing is often called the "carrier". You can buy new ones from Eaton or Auburn for around $300-$400.

Make sure you get the right series for your ring gear....

Steve McCorry - Central Ohio Camaro Club
'69 Camaro RS/SS-350 - Daytona Yellow
'95 Camaro Z-28 - Sebring Silver
click here to see my webpage ---> www.mindspring.com/~mccorry (updated 12/22/00)
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post #4 of 7 (permalink) Old Jan 10th, 01, 05:11 PM
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Call Mark at Pro Gear, in San Diego Ca. He is a wherehouse for Eaton (amoung others) and he is blowing this stuff out cheap.

858-571-1158 m-f 8-5pm
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post #5 of 7 (permalink) Old Jan 11th, 01, 08:10 AM Thread Starter
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Thanks for the info!!! The spider gears, ring & pinon,and the locking pin are all meesed up too. I was told the gears were 456 or 488 but, who cares about that now when I have to rebuild the whole dam thing! I was better off buying a 9 inch ford from moser or currie but, I wanted to keep the car with chevy parts so, I guess that's the price to pay! How can I tell if this is an original rear end fro a 69 or if it's not from another truck or car? The rear end has some numbers on the axle housing on the right. Will that help? The middle part has metal loops on it, like to pick it up with a hoist or something. I had never seen this on other rear ends on camaros, that's why I'm wondering about this rear end. Also, it has other welding marks where its been installed in other cars.I also called mark on that possi unit and the price was dam good, Under $300!!!! Thanks for the help!!!! I always wanted a street rod toy but, don't have the knowlegde on performance parts. I was about to buy a cone possi unit, but thanks to your help not any more. What gear ratio should I go wiht for street/strip performance? I was thinking of going with 411's. What do you think!
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post #6 of 7 (permalink) Old Jan 12th, 01, 11:28 AM
Join Date: Apr 2000
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Hey Crazy
Look at your ring gear if original it should have two numbers stamped onto the ring gear it should be something like 9,41 this represents a ratio of 4.56.1. Typicaly if you divid the ring gear number (high) 41 into the pinion gear (low) 9 you will arrive "close" Caution "close" to the ratio of the rearend...also "GM", a part number and the year Ex: 4,69 should also be stamped on the ring this represents April '69 build date. Your's of course is likely different..

[This message has been edited by wacky174 (edited 01-12-2001).]
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post #7 of 7 (permalink) Old Jan 12th, 01, 12:19 PM
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Location: Michigan ,USA
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Typicaly if you divid the ring gear number (high) 41 into the pinion gear (low) 9 you will arrive "close" Caution "close" to the ratio of the rearend

Just the opposite!!

Divide 41 by 9 = 4.56 ratio (exact)

ring gear/pinion=ratio (/=divide)


fyi Hollander http://www.hollander-auto-parts.com/...od_partid.html has a nice chart in their Classic Parts Indentifier 1960-1989 ISBN 1-882437-84-5 Book available on their site, cost around $50 but cheap at twice the price.

Here's the index to what it has;
GM Option Codes
Engine Indentification
Engine Application
Axle Ratios & Indentification
Carrier Assembly ID
Axle Ratio Charts
Tranmission ID

btw-all makes and models, Ford, Dodge, GM etc!!

[This message has been edited by elcamino (edited 01-12-2001).]
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