lmao i know wut yer gonna say.go do a burnout if it spins both tires you gotta posi.im buyin this 82 t/a with a 305 and a close ratio 4spd i test drove it an stuff but im not gonna do a burnout with him in the car,so how can i tell if its a posi or not its gotta drum brake rearend an i got no clue wut gears it has.he decomputerized an de smogged it also.it has a high preformance crane cam in it an chrome dress up stuff.iroc wheels an he wants 500 for it.{hes havin a kid so da t/a gots to go he said} its a 82 t/a hardtop and its red wit tan interior.whoa did i jus get off subject,lol sorry ,but can you tell me how to identify a posi rear without being able to roast the tires,btw my 89 v6 when the v6 was still in it ,it would some times spin both tires an it WASNT posi

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1989 pontiac firebird{trans am clone}
maui blue hardtop{new paint}
406 pontiac engine
demon 750 carb
crane roller cam@ 240 intake 248 exhaust
crane roller lifters & rockers 1.6 ratio
edelbrock performer rpm heads and intake
dynoed 457hp@5300 rpm& 503lb ft of tq@2490rpm
all the dressup stuff
12 bolt rearend from a 68 maro,3.73 gears now
17x9.5 zr1 rims up front
17x11 zr1 rims in back
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315/35/17 in back
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gm 6 speed transmission
centerforce clutch
pioneer cd deck,and changer
infinity 6x9's and 4x6's
2,profile california amps 640sx
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prolly 100 things im forgetting lol
o yuh its hella fast

 

g80 should be the code in the glove box. but, I would not worry about if it had posi or not you can fix that later.

 

Jack the car up and turn one wheel. If the other wheel turns in the same direction, it's a posi. If it turns the opposite way, or the driveshaft turns, it's open.

Even if it has a posi, it probably doesn't lock all that well and need to be replaced anyway. Almost 20 years of driving would weaken/wear the clutches. My 88 had 100,000 miles on it and with the 9 bolt, spun 1 tire even though it passed the above test and had a limited slip tag on the cover.

I'm sure somebody will correct the above test if i'm wrong, but it always worked for me.

 

Go find some dirt or sand or even a little gravel and goose it and see if both tires spin. Or put some water down and do the same thing. Any of these won't put a strain on the drivetrain and the owner should allow you to verify it's a posi, it's easier than jacking it up.

 

In addition, I have a posi and when jacked up my wheels don't turn the same way. This test is only to see if there definetaly is a posi in it, not to see if there definetaly isn't one.

Jason

 

If you want a "REAL" posi, jack it up, have someone hold one wheel, turn the other. If it does not want to spin, it's a "posi". if it does than have the other pirson let go.then spin the wheels agan. If they turn the same way, you got "limited slip". If they turn the opposite way, you got "open".

[This message has been edited by Mi82TA (edited March 29, 2001).]

 

just check the glove box! I have seen open and posi do all of the above. our posi is made by spring pressure holding the two outer spider gears against friction material. this is very weak and alows the wheels to move at diff. speed other wise cornering would result in wheel hop and sliding

 

First of all, positraction and limited-slip are the exact same things. I also have a "real" posi, meaning both wheels spins on launch and I leave two equal length tire marks when I launch, and my wheels spin opposite directions.

Jason

 

there are a lot of tricks for checking, like everyone said, but if i want to know i pull the cover. gives you a chance to look around, change the oil and add posi additive if you do have posi.

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ICON Motorsports

1st & 3rd

 

89 is correct "Posi" (or Posi-Traction) is just GM's trademark name for "limited slip". GM made a variety of different types of "Posi" (or limited-slip), but they are all called Posi-Traction.

If you don't have "posi", then you have UN-limited slip; or a "peg leg".

 

I bought a "Locked" rear rnd with 3.40 gears from the junkyard, and the gy told me that when one wheel spins, it does 3 complete turns and then the other whell kicks in, but on all my peel out m,arks they are the same length

 

There are alot of misconceptions about what a "posi" should do.

If you jack up the rear, and spin a wheel on an "open" rear, the other wheel will easily spin in the other direction.

However, if you jack up the rear of a posi, and spin a wheel, the other wheel will ALSO spin in the opposite direction. Whats the difference? The force needed to turn the wheel. What most people forget about (and this won't apply to you since it has a manual tranny) but most people who do this, leave the tranny in Park. With the driveshaft locked, both wheels CANNOT turn in the same direction. If they do, something in broke.

With a posi, the other wheel will spin in the opposite direction, but with great resistance, since you have to overcome the pre-loaded clutches in the carrier. If the posi is worn out, it will act like an open rear.

Oh yeah, and if you do a "peel out" in grass or dirt w/ an open rear, both will spin (usually) due to the limited traction.


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[This message has been edited by GMTech (edited March 30, 2001).]