Im not a gear/ axle type of guy but here i go, i checked my RPO and i have 2.77 gear ratio, but guys at work tell me to try to get 3.42 from an s-10, so i looked around and found some on ebay. But what i want to know is, are the stock rear ends 7.5? or 7.625? and what else would i need in order to install them, or is it a bad idea to buy from e-bay? im just a daily driver with a couple of mods, msd cap, rotor, wires, holley AFPR, Crank and Alternator Pulley, 160 thermo, so what do u guys think? im gonna keep on doing some research so any suggestions would be koo

 

7.5 and 7.62 is the same thing, even if logic would tell you differant. just Gms way of confusing all of us. you'd need an install kit plus the tools. i wouldn't buy used gears from ebay, but i have sold some on ebay

 

For starters, you have a 2:77 rear per your RPO then its a BW 9-bolt and any gears that you mentioned WILL NOT WORK with your set-up. They are ALL 10-bolt parts and are not interchangeable with what you have.

 

So there are 7.5 10 bolt also? so why would they mention they work on a 82+ camaro? what else would work on my camaro? cause from what i heard 3.73's lower your top speed

 

The Borg warner 9 bolt aussie Posi is an od ball rearend. Its not on alot of the cars. Its very strong, stronger than the 10 bolts but a PITA to get parts for. NOTHING from a 10 bolt will interchange with the 9 bolt. I have one, you can order used, remanufactured internals for 450 or new internals for 500. I am in the process of doing mine right now. They can be ordered in any ratio from 5 somthing to 2.77 I believe. Hope this helps. If you want you can replace the whole rearend with a 10 bolt off of a camaro or firebird or even a 4th gen if you dont mind your wheels stickin out a bit further.

 

I didn't know that RPO determined axle?

Anywho, the 9 bolt is easy enough to check, it has 9bolts on the rear cover! ....and I know at least my 9 bolt 2.77 has a little tag on it with the gear ratio.

The parts from a 9 bolt and a 10 bolt do NOT interchange, as Dewynter said.

If you have a 2.77 / 9bolt, you pretty much SOL like me. Since you need the carrier/posi, not just the ring and pinion, it's not cost effective to upgrade. It is a stronger axle, but still not worth puttin' a lot of money into IMHO. I'm swapping in a 3.45 ratio 9 bolt, but it's already complete with even the PBR caliper mounts, so it'll be a simple swap.

Before I found it, the plan was to rebuild a 10 bolt axle.

 

There is an RPO code that is for your axle as in my axle it was a:
G92: High preformance axle
G80: Posi
GM3: AXLE REAR, 3.45 RATIO

I was lucky to get the 3.45 factory in my car

 

hehe...were carrying this over in 2 threads!

....so my 2.779bolt would have a different RPO than a 2.7310 bolt. Makes sense.

So are ALL G92 cars a 9BOLT??????????

 

LOL 2 threads.

As for if al 9-bolts are a G92 im not sure. Wish I had the answer.
my 89 formula does not have the G92 code on my RPO sheet, but my 89 GTA did and both had 3.45 posi 9-bolts. Go figure. Both cars were identical in every option other than the GTA had different color, leather seats/w aticulating headrest, and ground effects.

 

aint it f68 for 3.45 gears? oh yeah if i find a 9bolt rear end with 3.42's i cant use them right, just because i have a borg-warner rear end?

 

Double Post


.

 

These are the most COMMON gear ratios for 9-bolt and 10-bolt


9-bolt...2:77, 3:27 and 3:45 (( BW rears Dicontinued in 1989).

10-bolt....2:73, 3:23 and 3:42

And these are not interchangeable.

 

Dammit, so im pretty much stuck with my gear ratios, oh well ill have to get back my tranny and engine work

 

The place I get my parts for my 9-bolt is Davenport Motorsports Calgary Alberta. They get them strait from the factory in australia. $500 for what ever gears you want its a great deal. I just replaced my 3.45 gears because they are best for me.
http://www.davenportmotorsports.com/store/index.asp
Give them a call they can hook you up with all the answers and info you want.

 

500 bucks? wow can anybody send me a check, thats the money i dont have, since i can only get 3.45 i think ill take my chances in the junk yards

 

Check this out i found this in fbodymotorsports.com

"One of the best ways to increase your car's performance is to lower your rear axle ratio (numerically higher) Moser offers the following ratios for the GM 7.5" & 7.625" differential found in 1993-2002 Camaro & Firebird: 3.73:1, 4.10:1. Manufactured to OEM specs and tolerances allowing for long life and quiet operation.

These 4.10, 3.73 or 3.43 Moser Gears will fit your 82-02 Camaro, SS, Z28, RS, Firebird, Trans Am, Formula or Firehawk. I put 4.10's in my 2000 Ram Air Trans Am and I love them."

and yeah its in the 82-92 section for thirdgens

 

That will NOT work in the 9-bolt though.

Sure it says 82-92...taht's because most third gens came with the 10-bolt rear-end. For a 9-bolt, you have to look for parts that say "9-bolt". Otherwise they won't work (except for brakes..brakes will work on either 9 or 10 bolt).

 

Oh Well, I Guess My Only Option is 3.45

 

Or 3.27 or 3.70

 

which ones would u recommend? and where can i find them other than a junk yard for cheap

 

Still will not work for you, 2:77 which you have now are 2-series carrier and those gears (3:27, 3:45, 3:70 and 3:73)will only fit a 3-series one. Again you are SOL.

 

but i can rebuild my rear right? cause when i do a burn out it only burns the right wheel, but, when i burn them in water both of them spin, i guess its my limited slip, or something is shot

 

I have a 9 bolt also. Right now the gear ratio is 2.77. I wanted a 4.10 gear, but I didn't need one, nor could I find that gear ratio for a 9 bolt. But I did how ever find a 3.42 carier from the yunk yard. I bought the carreir from the junk yard for like $50. And then i when to www.ring-pinion.com and bought a 3.73 gear for my 9 bolt. I bought the ring, pinion, bearings, and shims from around less then $300. Try that

 

By the way. If you don't know how to check if its a 3-series gear. Just pull of the diff cover, and count the teeth on the ring, and the teeth on the pinon. Divide the number of teeth on the ring by the numbe of teeth on the pinion