1985WS6transam

iTrader: (4)

Ok, i bought my car with the person telling me that it was a non posi 2.73 Rearend. It is a 1988 Formula WS6 suspension. I bring it over to my friends and we go down his block and do a quick burn out, 2 lines of rubber, confused, i do it again, another 2 lines. The person told me that he had just gotten the rear rebuilt and showed me the reciept. So I assumed he knew what he was talking about with it being non posi? Were all WS6 cars posi? Were all formulas posi? Do i have a posi??

2fast91's

well ihave a 88 gta trans am with ws6 suspension upgrade and i have a posi with rear brake discs,so if you said you have ws6 you have a posi rear end,because what my manual say all ws6 came wiyh posi.good luck

coolram62

iTrader: (2)

If your SPID decal is still in the car(and make sure it matches your VIN)look go code G80.This is the RPO for positraction.Even though it was part of the WS6 package it will still be listed separate(similar to 350 powered cars having B2L and L98 on the sticker).Also if the axle tube is clean you maybe able to get your axle code off of it.They were stamped in the front,facing front of car,on the right tube about middle tube.It will have the original axle code,indicate posi or non-posi and the build date.

1985WS6transam

iTrader: (4)

I do NOT have G80 but i DO have WS6 listed on the SPID sticker. I will look under the car asap for the axle numbers.

Edit: Just because i left 2 lines of rubber each time does that mean that i have posi or is it something else?

1BADROC

iTrader: (1)

Not all ws6 cars are posi my buddies 89 formula ws6 came with the same rearend 10bolt 2.73 gear non posi. Count your hogs head bolts if there are only 9 its definitely a posi all 9 bolts was a posi and it probably has 2.77's. Easiest way if its a 10bolt to tell is jack the car up with both rears off the ground turn the tires if they turn the same way its a posi if they turn opposite ways its open.

ScottyRS

iTrader: (2)

But...he has two rubber tracks.

1985WS6transam

iTrader: (4)

Hey, 2fast91's what manual are you reading? im just curious.

robotic_junky

I have everything off my 87 GTA with WS6 package in my 1991 Firebird. I have a hard time getting both tires going, if I'm lucky. The way the car drives, I think I have 2.73s because I cruise at 55, I'm guessing, at 1700RPM in OD, but the tach is off 100 RPM for every 1000RPM. So it would be like 1550 RPM at 55 MPH. Some people, who say they either worked or raced against my old GTA, say it has 3.27s. The axle is too dirty to find the code. I don't posi in my axle.

SR-71

Your '87 GTA should have had 3.27's. See www.f-body.org's technical database charts.

As best I can do the math, you've got 2.73's. According to the charts on F-body.org, if your '91 was originally a V8, then it's got 2.73's. If it was a V6, then it would have 3.23's.

To tell for sure--
Since you say not a posi, jack up one side of the rear and set blocks around the front wheels (for safety). Emergency brake off, trans in neutral. Slide under the car, and draw a chalk mark on the inner sidewall of the elevated tire. Turn the tire so the chalk mark is straight down. Draw a chalk mark on the very bottom of the driveshaft. Now rotate the driveshaft by hand, and count the number of rotations it takes to turn the wheel exactly one turn.

If it's in neutral and the brake is off, and you can't turn the driveshaft, then you have a posi. Raise both rear wheels off the ground. Turn the driveshaft. If both wheels turn the same direction, that proves it's a posi.

2-3/4 turns means you have 2.73's.
Almost but not quite 3 turns = 2.93.
Just barely over 3 turns = 3.08.
3-1/4 turns = 3.23
Almost 3-1/2 turns = 3.42
3-3/4 turns = 3.73.

Mongoose

iTrader: (2)

My '90 Formula has WS6 and was a non-posi car originally. I know this because I'm the original owner. It has had a 3 series Auburn posi with 3.73s in the original 10 bolt and now has a 2.77 posi 9 bolt. You may be mistaken about all 9 bolts being posi, I seem to recall reading somewhere on this site about some of them being open diffs.

1985WS6transam

iTrader: (4)

ok, Does 2 rubber marks indicate a posi rear??? That is all I am really wondering. But till then i will go outside and try and read my axle codes.

robotic_junky

A non-posi can hook posi, sometimes. Just do what the said lift up the rear and have tranny in N. Then see if they both go forward at the same time.

Mongoose

iTrader: (2)

Check for a stamped metal tag with one of the cover bolts through it as well. I know on the 9 bolts they had one tag stamped with posi info and another with gear info. I think the 10 bolts had the same tags.

1985WS6transam

iTrader: (4)

It has been raining out all day so nothing to get under the car, if my car came with that tag (like my old one did) the person might have taken it off when he got the rear redone maybe?? I know what your talking about but the tag from my old car is sitting on my wall in front of me cause it came off...

DJP87Z28

No RPO G80 means that this option for Limited slip (aka Posi) is not on your car.

1985WS6transam

iTrader: (4)

So it is confirmed from the above reading that i do not have posi. Thank you everyone but one last thing, why are there 2 rubber marks on the road if i do a burn out??

pizza_guy

Until you can verify WITH ABSOLUTE CERTAINTY whether one is in there or not, you really don't know by what somebody/some book has said.
These cars are 20+ years old. Anybody could have done anything to any of the parts being used in that amount of time.

Do the above mentioned tests to CONFIRM 100% one way or the other, then we can start debating the 2 lines of rubber.

Robotic_junkie says it just 'happens' sometimes. Maybe he could enlighten us.

84z28350

If you have enough power going through an open you can bake both tires without a problem....


I know my rear is OPEN for sure as i have been in there a few times, after i dropped in my new 350 it has no problem laying a couple hundred feet of rubber on both tires!

Now if i try to chop a nut in the middle of a parking lot i can start off with both spinning but as soon as i make the turn its back to one wheel Straighten out again and its back to both

robotic_junky

By what I know, limited slip, non-posi, will turn both tires over when one tire slips the other one will try to grab traction, but it doesn't always happen.
Example, if I WOT on a left turn, both tires will spin. The reason, I came up with and heard somewhere, The passenger side tire is the tire that usually get the power. Since the passenger tire is going a longer distance than the driver side tire. So the driver side tire will want to go that same distance as the passenger side. End result, you spin both tires and you go sideways.
If you are taking a right turn, since the passenger tire is one that gets the power first, you'll problably just spin the passenger tire. Unless the rearend thinks you need more traction, it won't kick in the driver side tire.
That's what I know about limited slip. Again, just do what a couple have side jack up the rear and spin a tire forward and see if one goes in the same direction or oppsite direction. If same direction, Posi. If oppsite directions, then it's a non-posi, limited slip.

That's more than 2 cents, but oh well.

84z28350

Typically an open will only spin the passenger side tire (the torque takes weight off of that side) unless you are in gravel or have enough power to bust both tires loose.

A limited slip/posi will only allow a very limited (hence the name) ammount of axle speed variance. So unless the clutch packs are burnt out of the thing from doing too many burnouts you will ALWAYS bake both tires

1985WS6transam

iTrader: (4)

Are you saynig that non-posi and limited slip are the same thing cause from what i always understood limited slip is posi.

1985WS6transam

iTrader: (4)

UPDATE: I just jacked up my car in NEUTRAL when i spun the pass side wheel foward nothing happened to the drivers side when i spun it backwards the drivers side would SOMETIMES spin fowards... Same thing happened when i would spin the drivers side wheel. In DRIVE when i spun one wheel foward the other one would go backwards but i dont think drive makes a difference does it? everyone for all the help.

EDIT: Oh and this car is ALOT slower then my old 91 bird so i dont think that it is making alot of power... As in the engine was just rebuilt but visually all i can see is a Edelbrock performer TBI intake and the guy told me it has roller rockers under the valve covers but not a cam or any thing just basically a stock rebuild... It is a 305 for sure. Stock rebuild on tranny also...

DJP87Z28

For your information a Limited Slip is not the same as open rear. Postraction (AKA Posi ) was Chevolets tradename for a Limited Slip rear in the Sixties. It just a name that people who don't know any better use

1985WS6transam

iTrader: (4)

DJP87Z28 im still learning here... I have always understood it as 84z28350 did. Thanks for clarifying that. So the question still stands, why do i have 2 burnout marks if im not making alot of power over stock??

84z28350

Its an open for sure. of a badly beaten and burnt out posi

In neutral it should have spun both tires the same direction if it were limited slip.


But like i said, enough power going through an open you WILL spin both tires.


BTW, yes posi is just GMs old name for limited slip! Just like other MFG's used their own name for it.

DJP87Z28

Stop the BS Post and go pull the cover and look what you have. You should change the fluid anyways. Also Burnouts don' t prove anything. example: the road surface could be responsible for the tiremarks.

1985WS6transam

iTrader: (4)

I jacked up the car to find out so that wasnt really a BS post... If it wasnt posi i was going to get rid of this rear anyway. Im saving up to buy a 12 bolt or a 9" ... thanks for all the help everyone

Zepher

iTrader: (1)

My 88 Formula had the 3.23 posi drum rear and my 90 Formula had 3.23 open drum rear end, both are WS6 cars.

Guest

Limited slip was option dependant most years on WS6 cars, although a few years it was part of the WS6 package. 88 the limited slip was optional on WS6 cars, but with some other options the limited slip became a mandatory option.

adampousson

when i had my lo3 with a 308 open diff i would spinn both tires,but only to a point.the drivers tire will always cut out after about 5-10 feet and the passenger will keep spinning.