just like it says, is my stock borg warner 3.27 posi stock? i only ask because i was going to burn off what litltle was left on my rear tires and i was only getting the passenger side spinning.

Thanks everyone!

 

Yes it would have come with posi.

Those frequently wear out, and slip with little or no limit; and then they aren't much different from an open. Sound slike that's where yours is now.

 

i wish i knew what you were talking about being open and stuff. so are you saying that stock it was posi and now it's working like a slip posi and eventrually will just be one wheel drive?

i've been thinking about changing it to 3.73 - if i did that would it fix my posi problem?

 

My old 87 GTA had the same rear end and gears and it was stock cuz the code said so on the car.

And do they really act like an open diff rear?? I did not know that... In that case is that a good rear to use on my 83 383 bird build?

 

"Posi" is nothing but an abbreviation of "Positraction", which was GM's trade name for limited slip for a few years. Alot like Traction-Lock, QuadraTrac, SmartTrack, etc. that you see today. All the same thing.

What they are, is some sort of system to allow the rear wheels to turn at different speeds but yet not go into one-wheel spin if one wheel loses traction, usually involving clutches. A differential is a mechanism to allow the wheels to turn at different speeds, as is required when going around corners; but without some method of "limiting" this "slip", no power whatsoever will be fed to a wheel if another wheel loses traction. Without some sort of a slip-limiting mechanism, it is an "open" one.

Most limited-slip designs, like I said, use clutches. Even if one wheel loses traction, some minimum amount of toruqe is necessary to break the clutches loose and allow it to spin, which sort of puts a "floor" on the amount of power that the other wheel will get. May not get FULL power, but at least it won't get ZERO, either. But the clutches sometimes wear from use, and eventually stop doing that, and then the whole thing acts like they're not there.... "unlimited slip" if you will.

The gear ratio has nothing to do with this. You can have any gear ratio, with "posi" or without it. So no, changing the ratio will not affect it. It is a separate piece of the rear. But if you pay somebody to do a gear swap, that would be the time to add posi too; rather than paying twice for all the disassembly and all.

On the other hand, you have a 9-bolt, which SEVERELY limits your options. There are basically no parts out there for it. You can get 3.70 or 3.73 gears, but AFAIK no parts to service the posi. It's possible sometimes, if it's not too bad, to take one of those apart, shim it up, and restore it to working; but not always.

 

wow, this is a strong arguement for just strengthening a 10bolt if you're not going to be subjecting it to more serious power.