Nobody is talking on the drivetrain board. I bought a used posi unit and i want to know how i can tell what series it is so i know what gears to put on it. I just dont want to open up my rearend again to find that i have to put it back together and go buy more stuff

 

I am not sure in telling but where did u get it from. That might help us a little better.

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Eric Natzke
91 Firebird 305 TBI
"It Ain't Stock"
http://members.aol.com/j007golden/91firebird.html
For info on certain parts or mods go to the site below
http://members.aol.com/j007golden/modeval.html

 

Cool! Another 91 Firebird Bandit II owner! Would you mind checking out my site, and see I have missed any information?

Http://Bandit2ProAmRegistry.Homestead.com/main.html

Thanks,
Clint



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1991 Firebird Bandit II Edition
Flowmaster 80 series muffler
no Air/Cat, straight pipe
no smog pump/pulley
K&N Open Element cleaner
Ultimate TBI Mods (port/polish, AFPR)
1" TBI Spacer .25" Injector Spacer
Homemade Subframe Connectors
GM Wonderbar
Waiting to install;
95 Z28 LT1 Camshaft
1.6:1 RR
Bryco double roller timing set
LT4 valve springs
36mm front, 24mm rear anti-sway bars
Polyurethane everything!
MacEwan Motorsports Silver-Faced guages
lead pedal foot . See my project rocket turtle @
http://oursportscars.homestead.com/firebird.html
Member of Tidewater Trans Am Club
www.ttac.net

 

I bought the posi off of Ebay.. im just wondered if theres any casting numbers or anything i can measure to figure out the series.. Firecrow, Thats pretty cool. Ive spent hours searching the net for any kind of info for this thing and havent found anything except from a few people here. mines black on black and still lookin good. im the second owner and i know the first owner fairly well. ill send ya picture if i can get around to it

 

Do you know what it came out of. Third gen or fourth gen F-body? Do you know the spline count to make sure you have the correct axles? If everything is go as fare as fitting your diff. then you can measure the thickness of the ring gear mounting hub. Once you have this info post it and someone with some expirience should be able to tell what series gears will work. I'll take a guess and say the thicker hub will take a 3 or 4 series gear. Anyone can butt in about now and correct me please.

 

Its a 7.5 with 28 splines which is what i need. i havent got a clue what it came out of. sitting on a flat surface it measures 2 inches from the outer hub where the bearing is to the top of the ring gear mating surface. the ring gear surface itself measures half an inch.

 

Thanks a lot. I am glad you liked the site. I am also glad to hear that you are taking care of the car, and upgrading it

 

Does anyone have a 2 or 3 series rear they can measure? This might help Bandit figure out what he has and what he needs.

 

As long as it has 28 splines you are fine. series 2 has 26 splines and series 3 has 28 there are some dimensional differences but as along as you have 28 splines you have a series 3

 

A 2 series has a thicker ring gear. This is why you can use 3 series gears in a 2 series carrier with a spacer plate. You can't install 2 series gears onto a 3 series because it just won't work without major machine work which isn't a good idea.
I don't have any measurements but if you go to a junk yard you could visually compare them!

[This message has been edited by JPrevost (edited November 03, 2001).]

 

Uhm, no, absolutely not! Series 2 and Series 3 refers to the gears, not the spline count. A 2-series gear or posi unit is anything 3.08 and lower. A 3-series is 3.23 and higher.

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1991 Camaro Z28
5.7L 5-Speed (originally 305)
317 RWHP, 418 RWTQ
13.23 @ 107.62 MPH (2.10 60')
Southern California
Member: SoCal 3rd Gen F-Bodies
Member: SoCal F-Bodies
-=ICON Motorsports=-