9 Bolt Posi fix

[DeWynter]

Where can I order parts for my 89 9 Bolt 3.45 Posi, It no longer is a Posi so I belive it needs new clutches or cones or what ever is in there, as im un sure what it is and I cant find a diagram. and Niether can GM

[M3EATER - GG '00 WS6 T/A]

9-bolt?

Is in the 89 formula that you show in your sig.?

The stock rear end in that would be a 10-bolt (refers to how many bolts are holding the rear cover on).

If the clutches in your posi are worn out, there are many possibilities in replacing it. You version of the 10-bolt is different from the 10-bolts in the 93 and later f-bodies though. Your axles are 26 spline (the later are 28 spline).

You can use a later 28 spline diff unit if you change to 28 spline axles. You then have the choice of the Eaton Posi (clutch type - very strong), Auburn (similar to a clutch type but uses male & female cones that press together - also strong), the Torsen diff - either a stock take-out from an LS1 F-body or the HD unit from SLP.

How much do you want to spend? What type oo driving do you do with it?

Gordon

[N20LT4Bird]

9-bolt?



The stock rear end in that would be a 10-bolt (refers to how many bolts are holding the rear cover on).



Gordon

Unimportant fact update - - - The "10 bolt" actually refers to the 10 bolts holding the ring gear to the carrier, but also conveniently corresponds to the cover bolt count.

[Joe 1320]

Guys, there was more than one rear used in 3rd gen f-bodies. Australian 9 bolts came in (3) gear ratios: 2.77 - 3.27 - 3.45. This rear end came in 1986,87,88 and 89 IROC's. Also came in 1987,88,89,90 and 91 Firebirds.

The 10 bolts are 7.5" ring gear and the 9 bolts
are 7 3/4".

I would suggest: www.thirdgen.org as a source to locate parts. You'll find what you need there.

DriveTrain Specialties (DTS) also carries rebuild parts.

[DeWynter]

Auburn (similar to a clutch type but uses male & female cones that press together - also strong), the Torsen diff - either a stock take-out from an LS1 F-body or the HD unit from SLP.

How much do you want to spend? What type oo driving do you do with it?

Gordon

I belive the 9 Bolt that is in my car, and belive me it IS a 9 bolt (their just a bit rare), is simular to the Auburn but I could be wrong. Also Im looking to spend no more than $800USD as Im from canada. As for driving I do, well a little of this, a little of that, down to the drag strip once a month or so (not anymore) a little bit of street racing and not to much spinning of the tires but I think I found a Place here in Calagry that will get me a new Differential from austrailia for $500USD plus labour. They specialize in rare Posi units, race level tranys and forced air induction engine systems. Thanks for the input though.

[M3EATER - GG '00 WS6 T/A]

[QUOTE=Joe 1320]Guys, there was more than one rear used in 3rd gen f-bodies. Australian 9 bolts came in (3) gear ratios: 2.77 - 3.27 - 3.45. This rear end came in 1986,87,88 and 89 IROC's. Also came in 1987,88,89,90 and 91 Firebirds.QUOTE]

I forgot that I had heard that before Joe. Good catch.