Schizo995

This has probly been asked 1000 times, but I have to know. When it rains and the wheels spin it feels like posi. In the couple of burnouts Ive done it usualy spins one, but like 2 times it spun 2. If I launch the car and let it spin it usualy spins 2. Is it posi, broken, or just confused?

sellmanb

if it spins 2 ever, you got posi. You probably just need to put more posi fluid into your rear end fluid.

nidyanazo

How do you fill up the posi fluid? Do you take the diff. cover off? of is there some little plug-bolt?

Screamin86

iTrader: (1)

ive sorta wondered the same because in my 86 T/A sometimes i get boh goin and the majority of the time its one but like you said in the rain depending i get both of them goin and slipde side to side but ive been told its limited slip because it alternates back and forth i too would like to know about this

86z/92rs

There is a plug on the rear end located on the passenger side rear housing. Can't remember if it's a 3/8 or 1/2 drive to remove the plug.

sellmanb

i thought that limited slip was the same as posi just different names.... shows what i know

parks911

Posi fluid? Do I add that in the tank next to the blinker fluid & the headlight de-icer?

Screamin86

iTrader: (1)

hey you forgot the muffler berrings.

Screamin86

iTrader: (1)

im not to much on rear ends but i thik that limited slip will get both but majority will get one but i could be wrong. but ive kept one rollin for about 50-60 yards w/ smoke rolin off my left rear tire oh yea what about those muffler berrings

Benm109

They are the same thing. Limited Slip, Positraction, and Chyrsler's SureTrac (or whatever they call it), are all basically the same. Those are NOT open differentials.

Your RS most likely has an open differential, NOT a posi or limited slip. The only way to truly tell is to take the rear cover off and examine the differential. If all you see is spider gears, side gears, and a cross shaft, than you have an open rear. If you see all kinds of clutches and stuff, then you have a posi or limited slip differential

It is possible to spin both tires with an open differential. I have done a burnout before in which both tires broke loose, yet I have an open rear. It just happens sometimes.

To change the rear differential fluid, you take the rear cover off, let the fluid drain out, scrape the old gasket material off, reinstall the rear cover with a new gasket, then force new axle oil into the rear diff. by unbolting the 3/8" plug located on the passenger side of the rear diff. Once the fluid begins to come up to the level of the plug hole and begins to seep out, put the 3/8" plug back in and your done.

The type of fluid you need depends on if you have an open diff. or a posi diff. There is such a thing as "posi additive" fluid, which is highly recommend for posi differentials.

ShiftyCapone

iTrader: (7)

Less than 1% of all RS cars on the road had the 2 serries posi. Very rare but could be had.

Screamin86

iTrader: (1)

so it is possible to get both tires goin with open dif. i mean i get em both goin alot and depending on how im sitting or what the car decides to do it will get one why is this or what do i have?

Benm109

Yes, it's possible, but not probable. It's kind of like what you said, it just depends on the situation. But, like I said, the only 100% way to know is to take the rear cover off and examine the differential, or even identify what type of rear you have, a 9-bolt or 10-bolt.

ShiftyCapone

iTrader: (7)

You can check RPO codes but they only tell you what the car came with. The only way to accurately tell is to pull the cover and look. Your rear end fluid probably needs to be changed anyway.

Screamin86

iTrader: (1)

its a 10 bolt w/ 2.73 gears we thing cause im runnin 1900rpms at 75. but like the other day ago i just pulled into my driveway straight and did a small burn out and got both goin real good. ughh im confused. im planin on changin the fluid when i get my 3.73's theregoes my gas mileage

rbjones

Sometimes, too, the clutches in a posi unit burn out, like if someone ran a small temporary spare on the rear for a while causing the rear tires to run at different speeds. The posi unit tries to work but, like a weak clutch, it just won't hold. Your 90 wt. will smell burned, like bad tranny fluid, if this is what you have.
Some posi units are rebuildable, some not.

Screamin86

iTrader: (1)

well id like to find out but if it isnt already a posi im either sticking in a set of 3.73's and a spool or find a 4th gen rear for cheap

Dewey316

Go to a GM Dealer or any parts store. They sell Limited Slip additive, It is no secret that you need to add it to your gear-oil when you fill up the rear if you own a clutch style limited slip. Now don't you feel like an *** for opening your mouth, with a smart *** comment, about a product that does in fact exist.

BIGJON

sellmanb

Thanks Dewey, that post bugged me... even made me do a to make sure there really was posi additive/fluid! Maybe it's just a secret to the non-Oregonians lol

Night rider327

iTrader: (13)

1) all clutch type limited slip rears needs posi additive. Some fulids has it already mixed in (redline for one), some don't.

It's an anti wear lube for the clutchs in the rear. If you have posi and your fulid don't have the additive in it, you will need to buy a bottle of the posi additive from a GM parts dealer


2) limited slip, posi, sure grip, etc are all the same thing, just diff words.

There's only 4 types of rears...
Open (1 wheel pulls)

posi/limited slip (both wheels pulls but one gets less traction than other)

Locker (both wheels gets the same traction/same torque, the locker will ratchet between one wheel and two during curves)

Spool (locks both wheels solid together, can not let the outside wheel turn more/less during curves)

You DO NOT WANT A LOCKER FOR ANY STREET USE!!!

Stick with limted slip or a locker if it sees alot of curves, street driving. etc


3) an open rear will spin both tires when the cross pin starts to wear, and only then. A limited slip rear can spin or or two, but if it does thats also showing wear. Most of the times the rear just needs more posi additive, other times the clutchs are worn

Screamin86

iTrader: (1)

well this morning i was runnin late for school and i took a back way and i came around a turn from a stop sign on a back road and stomped it and got both goin and got sideways and then the power you could feel alternating from wheel to wheel and the back was goin from side to side w/ that so does this mean i have posi and one of the clutches is sliping or somethin. and i know this the wheel that will usually spin the most from a standstill or burnout is the right but sometimes the left but whenever i come out of a stop sign or get out of somewhere sideways i get both alternating. i have a friend w/ a 84 T/A t-5 and he found out he has a posi because he took the rear apart and he too has this prob so is this how it works or does it need a good fluid change/rebuild or just a new rear?

Ron U.S.M.C.

The only problem with looking inside the differential is if it is the Auburn cone style posi can you see from there how worn down the cone is ?

Find yourself a patch of asphalt and power brake hard (burn out )for a few seconds. Have a friend watch or just look for either one or two BLACK burn marks when you're done. The break should hold one wheel still while the other spins if its a non posi. or both tires will spin indicating a working posi. If you get what looks like you did spin both tires for a sec or two than its a posi. that's wearing out

Do this out in the country somewhere or a very isolated spot.
Cops don't like it and either do most other people.

big gear head

Hey Ron, did you look at the date on this? 2004.

terrytunes

My 98 camaro v6 auto has limited slip, im100% sure same rear end as z28.

Ron U.S.M.C.

Sorry about that.
I was up late and tired ( 1:03 am )....

Eaton came out with a L.S.D. that they actually called Posi. .= http://www.eaton.com/Eaton/ProductsS...als/PCT_339923

Since then using the name has become common place to describe a L.S.D.