I'm asking because I simply can't afford the www.9bolt.com stuff, as much as I'd like to. The finances just didn't work out. So instead, I'm gonna go around the junkyards and see if I can find an old diff I can just take out. Iknow the quality won't be the same, but for now thats ok. I just want the shorter gear, and I won't be making the power for a while . So which GM cars came with the 9-bolt 3.45 posi? Thanks.

 

None. The 9 inch is a ford rear end. You want a 12 bolt that came out of chevelles and a bunch of other old school cars that I cannot remember off hand. I would just rebuild you 10 bolt that you currently have. if you are not running slicks and don't have that much power the stock rear will be fine. Add a posi and a set of gears along with a rebuild kit to that and be done with it. When you are running slicks and putting down serious power, than look into getting a stronger rear end.

 

AHEM!!! 9 bolt is the Borg Warner rear end that came in many, many F-bodies stock. :lala:

 

Specifically, '85-'89 TA's, GTA's, TTA's, and IROC-Z's (possibly others but those I know for sure.) AFAIK no other GM car ever came with a 9-bolt rear, as the whole purpose of it was to stand up to the torque of TPI and nothing else had TPI save the 'Vette which had a Dana 44 IRS and therefore didn't need/couldn't use a 9-bolt.

 

He forced me to read my entire post again, and yes, I did say 9 bolt. Thought I was going crazy.

As for not being in other cars, thats disappointing. I thought it might be in some trucks, but I figure every one in an f-body would be picked clean throughout the entire city by guys that were on the ball a LONG time ago. I was hoping I could get one off a truck that nobody suspected of having a strong 9-bolt.

Did they all come with the same number splined axles? Just wondering because apparently, the 9-bolt I have did NOT come on my car, and I have no idea where it came from.

I don't want to pull my axles off to find out, my dad would be like WTF are you DOING! Not that I'm not capable, just that my dad is tired of seeing my car torn apart (like NOW ) and I always end up driving his Jimbo. (My balancer slipped and I messed up the crank threads trying to put it back on....easily fixable but I decided to order a Fluidampr...) ANYWAYS!, so here are the current questions....

1) No other applications?
2) Is there more than one spline number my axles could have or just one? Thanks.

 

I thought he was refereing to the ford 9 inch. Sorry bout that. I did not realize that any other rear end went into f-bodies except the 10 bolt. Why did GM continue to use the 10 bolt in the fourthgen when the power level really increased. Is that because in 1990 they upped the splines on the axels? Which rear end was the australian one?

 

9 bolts have 26 splines through '88 IIRC, '89-'92 have 28 splines. Double check me though since I'm going from memory...

 

Is there any way I can identify what I have by getting the numbers off the differential?? I mean like can you tell what year it was by the numbers on the diff. cover, so I can know how many splines I have...

If not, whats the easiest way to find out how many splines I have? Thanks.

 

That's not correct. ALL 9 bolts were 28 spline! Almost all were disk brake. All 9 bolts have 9 bolts on the rear cover and 8 bolts on the ring gear.

Miles

 

That is wrong. 10-bolts had those spline counts, not 9-bolts.

AFAIK all 9-bolts have the same splines, so the axle spline count is not an issue with them.

 

Cost. The 9bolt is Austrailian.

 

Thats right, not that the 9 bolt was too expensive to build, but they didn't want to pay to import it from austrailia forever. It's accually not much more expensive than the 10 bolt, but almost as durable as the 12 bolt from what i hear. i hear it's good till 11's