Hi:
This is a 92 RS convertible that I bought last week and somebody wanted to make it Z28, I guess. On the option list it has auto tranny code but it has a T5 which really looks factory installed. Also, it has rear disc brake (with no code on t he option list). I think the axle may have been swapped since based on the option code it suppose to have 2.73 gears but when I jack the car up and count the tire rotations versus drive shaft I get 3.25 (one tire rotation for 3.25 driveshaft rotation). Also I see this tag on differentials and both rear tires rotate in the same direction. Of course taking the cover off is the best thing but I was wondering if based on this info and the pictures you can give me what axle this might be and if it is a posi.





Thanks,

 

9 bolt

 

Borg Warner 9 bolt. Almost all of them had the Borg Warner cone type LSD in them. 3.25 was an available gear ratio.

 

I don't think so... the closest ratio to that was 3.27. That might be what you have although I'm never inclined to trust the "spin the [blank]" guessing game.

The 9-bolt was officially discontinued in 89 although a few early production 90s got one. Obviously it came from some other car though I think you already knew that. Also as you probably have noticed, that stooooopid rubber plug leaks like a … I won't say that, it's not politically correct. Time to get rid of it by tapping the hole to ½" pipe thread and putting in a brass plug. Looks like it leeeeeeks so bad, it's probably empty. Do something about that right away.

The gear "series" are similar to the 10-bolt... 3.08 and down are 2 series, 3.27 and up are 3. AFAIK they were all posi. Virtually all had disc brakes though there are a very few with drums. Most of the discs are the crappy Saginaw system with cast-iron calipers. Only 89 got the better PBR with aluminum calipers.

 

Yeah, I got the 3.27 and 3.45 mixed up. There is a 3.45, right?

 

Thanks for all the information.
Sofakingdom: The calipers seems to be aluminum. Sorry about my ignorance, so this axle came from a 89 or earlier Camaro? I just want to know what kind of replacement part I can get for it since it needs rotors and pads.
Thanks

 

Only 89 got the PBR aluminum calipers. So you need to order pads for an 89.

GD

 

Pads are same 89 92. Hell you can even buy vette rear pads or early 4th gen

 

In addition the 88-back calipers being cast iron, they are easy to identify by their position: one is behind the axle, one is in front. The 89-up aluminum ones are both behind the axle.

9-bolt & 10-bolt had the same brake systems, in any given year. 88-back got Saginaw, 89-up were PBR. So if your rear is a 9-bolt with PBR calipers, it has to be 89. Order pads for 89-92 Camaro/Firebird w rear disc brakes.

BGH, yes, there was a 3.45 9-bolt ratio. Came in the 305 5-speed TPI cars w/ G92. In fact there was a 3.70, stock, as well; came in 85 Firebird L69 cars. (all 10 of them or whatever... it's pretty rare) 2.77 came in most of the TPI auto cars; 3.27 came in the automatic G92 ones; 3.08 came in some of the 5-speed ones.

 

Yep, both calipers are in the back of the axle, so it 89 up with BPR calipers and 3.27 ratio with posi.
I learned one more thing about this car
Thanks

 

Good deal, that's a relatively desirable rear axle. Would probably sell quickly on the classifieds on this site, for a good price, if the car ever got wrecked or something terrible like that.