pilgrim

I just got a 91 RS convertible for my daughter, and it's pretty bad on low traction surfaces. She won't be driving it much this winter, but next winter I'll put snows on it and she'll need to drive it. It's the standard 305 with an automatic tranny, not the high output 305.

I'm thinking a posi rear end would be a big help for winter traction, but although I've done plenty of mechanic stuff for 30 years, I'm still learning my way around the Camaro. No big deal, looks like all the cars I grew up with...but this group probably knows the answer to my questions.

1) Other than the factory build sheet, I'm thinking the best way to ID the rear end in this car is by number of bolts on the cover plate and checking the gear ratio, right?

2) What year range of posi rear ends would work with this car? I assume most 3rd gen rear ends would work, but what about earlier and later generations? Does it all just come down to bolt pattern and ratio, regardless of the year?

Any suggestions and places to look for a posi rear end would be appreciated. TIA, folks.

MrDude_1

you have a 7.5" 10bolt rear.
around 89 they changed the spline count of the axles in the fbodys. the old count was 26. the new one is 28.

so pretty much any 89-2002 posi would work... i would be looking on the 4thgen boards for one, since ALOT more of them had that option, and they sell them cheaper.

any of the 7.5" 10bolt rears with 28 spline axles will work. this includes S10s.. and possibly Gbodys.. athough you might want to do some research there.


of course the carrier series has to match the same as the gears you have.. or swap gears...

the rearend and transmission internals are my only really weak points on these cars... so i cant tell you too much... ive never setup a rear.. i just swap in a whole new one... you can get them from 4thgen cars pretty cheap.

hdtripp

Just a thought. I haven't run my firebird with snow tires, but it's so light, that with just regular radials, it's pretty bad on hills, doesn't have much traction. You might want to put some extra weight in the rear.

Gladstoneiroc

iTrader: (1)

Its probably a series two carrier currently with 2.73 gears, so the 89-02 posi wouldn't do you much good unless you changed gears. And by the time you change gears you might as well have waited and found a complete posi disc rear with the gears you want.

Nocturnall

You can get used gears and a used posi unit pretty cheap.

http://www.tacreationsusa.com/ has a posi unit for $100 and 3.42 gears for $65. It's all used stuff though and I'm not sure what kind of a life those components have. www.thunderacing.com you can get an install kit for the rear end.

pilgrim

AH!

As much mechanical work as I've done, I've never had to get inside a third member - I've only replaced them whole when they failed. So I haven't had experience taking a differential apart - not that I'm unwilling. Can't be any worse than replacing all the bearings in a T-5 transmission.

Are you gents saying that the posi unit can be installed without replacing the entire differential? It sounds like that's the case from the comments above.

91CamaroDude

why cant you just take the old ring gear off the old carrier and put it on the new posi carrier? a 10 bolt is a 10 bolt right?

im asking for myself, im looking at a 7.5 inch posi on ebay.

in the description it says... "this will take from a 3:23 gears down to a 5:13 gears its in great used shape and ready to install on your car" whats that mean? will it work for me?

Gladstoneiroc

iTrader: (1)

91CamaroDude, if you still have the factory rear that posi will not work as is series 3, and you are series 2 with your should be factory 3.08

ShiftyCapone

iTrader: (7)

The A4 TBi cars came with 2.73's. The T5 cars with 3.08. They are both used with a 2 series gear. I would look for a posi and 3.42 gear set out of a 4th gen. Buy a rebuild kit and have at it. You may want a shop to install everything if you are unsure how to properly set up a rear end. You could do this swap for under $500. That includes labor and an install kit if you choose to go that route.

91CamaroDude

here's the link to the posi i wanted http://cgi.ebay.com/ebaymotors/ws/eB...RK%3AMEWA%3AIT

i thought i was a great find. now im all bummed out.

my freind was just driving his stroked 333ci mustang down the highway the other day and thinking he was cool, he tried to race a WS6 trans am. the mustang jumped on the gas first but the trans am came back to destroy him, it wasnt even funny.

....definatly saving for my LS1

pilgrim

I learned from Fair Auto Wrecking in Denver that they have complete rear ends in .308 and .273 with posi - just $300 each.

I think I'll plan on just doing a rear end swap this summer. The price is right and it will only take a day to do the work.

AgentD

I have a 91 RS with the v8 auto also. I've rebuilt and replaced the engine in my fiero a couple of times but I don't know much about true RWD cars like the camaro. How would I replace the rearend with a posi rearend and change to around a 3.63 gear ratio? I'm hoping to make this into a drag racing car with minor road driving and since its a weekend warrior gas mileage doesn't matter. Where would I find the parts needed for this?

pilgrim

Here's what I've learned from this thread and other discussions - unless you want to take a rear end apart and rebuild it (not my idea of fun) I'd look for a complete rear end with the gear ratio you want - and swap out the whole thing.

SLP IROC-Z

iTrader: (1)

your better off buying a complete posi rearend. i sold two drum brake 3.08 posi 10 bolts, one for 100 bux the other for 50 bux. so they are out there for cheap money.