My 92 RS RPO codes say I have a 2.73 rear end.. I am sure it is a 2.73, but it seems to spin both wheels (no one patch scratch).. At this point, I don't believe there was a 2.73 posi rear end made.. Does anybody know if I have posi?

 

Some 2.73's were equipped with limited slips. Check the following FAQ for the kind of info you're seeking:

https://www.thirdgen.org/forums/tran...-10-bolts.html

JamesC

 

If you put a floorjack on your rearend and raise up one tire and see if you can spin it, you don't have posi..... should work.

 

If you're spinning both tires on pavement, you almost certainly do.

 

nah not exactly true, my dually has been in a lot of burnout contests, no posi and it smokes all 4 until I get into a turn or a weight shift.

my Camaro was the same way, but launch off a stop light and take a turn i got a one wheel peal.

he could have an additive or just grit making his rearend bind more... but maybe somebody tossed one in along the way.

 

In a light rear wheel drive vehicle the weight shifts left so the right tire is the one that spins. You would have to have equal traction to get them both spinning without posi. I don't know about your truck, but I've owned a lot of Camaros. They all needed a tight posi to not be "one wheel wonders".

 

In 90-92 Camaro and Firebirds you had three 2.73s , two of them being posi . If you can get the code off the axle the codes are 8HP for 2.73 open , 8HT for posi , and 8HE for posi .You can also check your RPO codes to see if it came posi or not . Or you can just pull the rear cover and see if ti is a 2.73 for sure and if it is posi .

 

Check the RPO list for code G80. That is posi-traction option code.

 

Guys,

All this is pretty much covered in the link above.

JamesC

 

my RPO says GU2 ... no G80. I'll have to jack up one wheel, or look at the axle for the code stamping. I like the way it lopes along on the hway at 1800 revs at 70 though.

 

I'm not crazy about relying on RPO codes (who knows what's happened in the years since the car was new), but if yours is correct and G80 isn't listed, your car has an open/standard diff.

JamesC

 

I agree .

 

Pull the cover.

 

If i pull the cover, mmmm what do i look for? I just replaced the fluid last fall. what a pain in the BUTT

 

For some reason, kid, people are loath to do that (seems to be a last resort), even though the fluid in many cases hasn't been changed in a decade or more.

Stevolwevol, pics of a standard/open diff, as well as two OE limited slips, are furnished in the link.

JamesC

 

I just looked in the console at the RPO sticker. Is your sticker still there? See how mine has GU2 and then G80 next to it.

 

Hey rich.. My RPO's only say gu2. no g80. I did not have the rpo's in my console, but I had the chevy dealer print out mine using my vin. I am gonna have to check by way of lifting one tire and see if it spins i guess. Maybe they screwed up (GM) and did not put the g80 on mine. I have an 86 IROC also, and it doesn't have the rpo's for posi, but it has it. My mechanic told me it has posi. I know it has 323's due to the way it revs at 70. I don't know the history of the iroc, but either GM missed something, or one of the previous owners switched it out. My rpo code in the iroc is gu2 which is 273 open..

 

yeah James, I loath changing the diff lube. I broke a bold off the darn thing in the process on the RS. I do like the smell of the stuff though..mmm ahhhhh I am a fanatic about keeping things lubed. I am willing to turn my self into a pretsle if i have to

 

Yep, GU2 is 2.73 ratio. As for the posi, I verified it is a posi when I had it jacked up (to remove the gas tank) and both wheels spin together. On yours, someone probably switched out the open end.

 

Hey Rich... when you spun the wheels together, did they both spin in the same direction, or did they spin opposite?

 

They spun in the same direction at the same time. Just jack the rear up so both tires are off of the ground, spin one side and watch the other (if you haven't done so already). Then let us know what you have.

 

hey rich.......... I saw in my owner's manual under features & controls: limited slip as being standard. Other features like cruise control have (optional), and limited slip did not have (optional) next to it.

 

ok, I was reading through some posts on locking rear, limited slip, posi, etc. Some people use the terms to mean the same thing. I was under the impression that limited slip, locking rear, and posi were the same thing. Am I wrong on this? I may just pull the cover off of the rear.

 

From what I read Rich, they are the same thing. Limited slip, posi, are the same.