I have a 89 RS with an auto and i was wondering if it has a 9 or 10 bolt rear,I would check but the muffler is right in the way . It is a posi, but i didnt know that RS's had a posi is this rare?
thanks for the help

 

I think they used 9-bolt on all 89 models except the 350w/G92. Not 100 percent though.

 

If you would check the tech pages om this site you would find out what rear came on the RS. But for your info: Auto 10-bolt 2:73 and T-5 10-bolt 3:08. RPO G80 Limited slip was available as a option on this model. but was rarely requested or ordered on Dealer purchases.

 

His info is right on the money. As far as it being a nine or ten bolt, I'll bet my bottom dollar you have a ten bolt. The nine bolt was the "heavy duty" rear axle, and usually the only 89 cars I've seen it in are GTA's and Irocs. My 89 RS auto car came with a 2.73 geared, non-posi ten bolt. It is somewhat rare to get posi in a RS. If you can find your RPO sticker (it's usually located in the console glove box), you should find these: GU2=2.73 ratio, and G80=positraction.

 

G80=Posi traction....hmm never knew that.

 

9 bolts were usualy used in formula 350 cars and gtas also iroc 350 cars..rs camaro got 10 bolts usualy 2:73 non-posi

 

Your lucky if you dont have a 9 bolt. Gears are so hard to find for them its crazy.

 

yeah but the stock 3:27 or 3:45 should do fine in these cars..but if you brake the pinion gear they are hard to find...I don't think anyone makes the gears anymore?..I had both and sold them Should have hung on to them a little longer

 

My car came stock with 2.77's and a 9-bolt. I know you can get 9 bolt gears a 9bolt.com, and I think Yukon makes them. Everyone makes gears for 10-bolt though.

 

wow..2:77 I never seen one..I know they exist but all the 9-bolt I had were mostly 3:27 and 1-3:45 I just sold my 3:45 9-bolt last week.....and the 3:27 3 weeks ago ....but may have acess to another 3:27......are you going to upgrade? How much are gears on that site?

 

RPO G80 is a Limited Slip. The name Positraction (AKA Posi) was GM name for Linited Slip axle and this name has not been used since the 60 or 70s.
Now just a slang term used by the unknowing.

 

i have 2 nine bolt cars my 85 T/A with lg4 5-speed came with the 3.27 9bolt and my 89 iroc came with 2.77 rearend gear. i swapped rearends from car to car. most of the 350 cars i think got 2.77 and most of the 5-speed cars got 3.27 but im not sure makes some sense i think tho. I have never seen a rs with a 9 bolt and i havent seen a posi rs. i had a 85 iroc with a locker rear i dont know where it came from it was factory rear disc had drums so i know it wasnt stock.

 

 

Step one.

Crawl under car

Step two.

Count bolts

Yes it is that easy. RPO codes only tell you what the car came with from the factory. Camaro Joe could have swapped rears or gears in his back-yard ten years before the car landed in your hands. After you count the bolts you will have to pull the cover and check to see what gears you have. That is the only way to be 100% certain. It removes all doubt.

 

Good Idea It took me a while before I found out the easy way lol.

 

Positraction-Limited Slip, tomato-tomato. The unknowing and the knowing alike use both terms, but yeah, if you want to get downright technical about it, limited slip is the term used nowadays. Everyone has their own definition of terms. Mine goes like this: Positraction or Limited Slip refers to any clutch type differential. Then you have the Lockers, then you have the race only spools and mini spools. Everything else is an open or "peg-leg" differential. Oh yeah, and if you have money coming out your ears, you can always pick up one of the new auburn ect-ed electronically operated locker differentials. You also have the zexel-torsen, which is a traction biasing differential that uses gears instead of clutch plates to control traction. The only aftermarket gears I've ever seen available for the nine bolt rears is the 3.70 ratio, and they're quite expensive. As far as the factory nine bolt ratios, 2.77 and 3.27 are pretty common. The 3.45 ratio is by far the hardest one to come by.