I have an 84 trans am with a L69 and with 4 wheel disk brakes and a 3.73 ring gear, but how do I know if I have a Posi or not. Is it in the RPO codes?

 

yeah, but that doesn't mean it hasn't been changed i nthe last 20 years. only 100% accurate way to know is to pull the cover and look

 

Alright thanks.

 

under the center console is a list of the RPO codes for your car. (if it hasent been changed either). the code for the "posi" rear is G80.

 

sweet thanks plumminfool

 

You can do a burnout and have a friend look at your wheels. If both spins... it is a posi. if only one wheel does, it's not.

 

Hah...never thought about that

 

hey you took the words out of my mouth if ya don;t mind putitng the stress on your tranny just burn those babies off, however if the posi unit is shot it'll on;y burn one tire anyways, so the best way to tell as they said above is just pull the cover and take a look. Cause i have a 84 with the L-69 option mine is 3:73 Posi however we didn't need that little wussy 305 so we got a 350 so Posi saves my ****

 

one tire spinning or one tire mark doesn't mean it isn't a posi. only way to know for sure is to pull the cover and look

 

might as well pull the cover... check the ratio and if its a posi or not...


then replace whats probly 20 year old gear oil with some fresh stuff.

 

Well, in a practical sense, if the posi is broken and you only see one tire spinning, or one tire mark, is that really different than not having a posi? You are going to be buying a new posi-unit anyway, so it really doesn't matter. If it just isn't there or if it is broken... does it really make a difference?

 

Yeah it makes a difference, because if the posi is worn out you can just rebuild it rather than having to pay $350 for a new unit. The clutch kit is like $55.

 

Cant you jack up the back of the car and turn one wheel and if the other wheel spins the same direction, you have posi, and if it spins the other way you dont?

 

I think you are right, I have done that on my 92 RS. I wish I had a posi!

 

i think if you turn one wheel, the other wheel will turn in the other direction. dont quote me though.

 

If the car has a posi and you turn one wheel clockwise (when viewed looking directly at the wheel) the other wheel will spin counterclockwise (when viewed looking directly at that wheel). It makes perfect sense if you think about it. The posi is effectively making the axels into one axel that goes all the way through the housing.

An open rear doesn't do this. Instead the spider gears spin and cause the opposite wheel to spin clockwise as well.

 

None of this crap about turn one wheel, or see if there's 2 marks, is really conclusive. Decoding the codes is equally worthless, since people change stuff all the time and don't bother to go back and re-stamp the codes.

Forget all that nonsense and gibberish and "I think this that or the other" garbage. Back to common sense. Take off the cover and look. It's the only way to know for sure. All the rest is mere guesswork and monkey-spank and idle conjecture.

Have you changed your rear end fluid lately? Then most likely it's past its scheduled interval. Go do the overdue maintenance, and while you're at it, make a point of looking at the carrier, and see if it's a posi.

 

I agree with RB, since the wheel test will only work if the posi unit isn't fried. If the clutches are toast or the spring is collapsed it can easily pass for an open rear.

Since you'll have to jack it up to change the fluid anyway try the wheel test and see what it tells you. Then see if you're suprised by what you find under the cover.

 

i think the real question is "how do i keep from having to get under my car and get my hands dirty" and "gear oil stinks"

 

The one advantage that open rears have over a posi is that they don't require that friction modifier. Talk about stink! That stuff could gag a maggot or choke a donkey.

 

I disagree dude, gear oil just plain stinks, I put the additive in mine and the stench of the gear oil is so strong I can't even smell whatever else is in there.

 

Even stink would say that stinks!! Its like when you go into an apartment building and you're like "Whats that they're cookin'"? That, plus CRAP!!

hehe... Fat Bastard rules...

 

Oh gear oil definitely stinks, but open up that little bottle of posi addative and take a good long wiff sometime. I bet you fight the urge to puke.

"Everyone loves their own brand."

-Fat Bastard

 

Hmmm, I guess I never did smell it. It was in like a toothpaste tube, I was pretty close to it under the car and I thought it was odorless, but then again I had a cardboard box with a trashbag full of 15 year old gear oil right next to me probably covering the stench not to mention my clothes. But man, gear oil is just bleh.