Ok, here is the story.

Today I decided to take my car out to a piece of deserted road and do a quick test to see if my posi is working or not. Seeing that all last summer I babied the car and rarely smoked the tires I really wasn't sure if I was pulling "one legged monsters" ...

So I step on the brake and the tires or shoudl I say tire breaks loose...tires are spinning, smoke is pouring out so I shut her down...I get out and feel the passenger side tire, ummm it's nice and warm, so far so good..I step to the drivers side and feel the tire....cold!!! Arrrgghhhhh!!

So my posi is shot right? I am almost 100% sure it's a B/W 3.27 posi rear, that is what the RPO codes read and I did the " Leave it in drive and hit 74 mph, take the RPM's and divide by 1000" , sure enough the math works out 3.27 (or very close to it...

So how can I be sure if it's shot? And what can I do to fix it? I guess there is no way to fix it is there other than getting a new rear end

Comments? Suggestions? Can I still drive it around like this without hurting it anymore?

 

There's a tech article on shimming the clutches in these rears. It's common that they get weak after 50,000 miles or so...


https://www.thirdgen.org/newdesign/t...tservice.shtml

 

as a side question, do camaros have the rpo codes printed in the center console like firebirds?

 

Well, I've seen them under the console lid on camaros in junkyards, but my car has it in the little compartment in the hatch.

 

I'm having the same kind ofproblem with my rearend. My car used to be able to do a mean a** donut at the drop of a hat! But now it goes about half way around and only one tire starts to spin. So, thats my test. Find a parking lot somewhere late a night, start from a dead stop, turn the wheel some and mash the gas! If it pulls more that a 180 you're OK! Oh, or you could jack up the rear end and spin the tires. If the rear is good they both spin the same diection, if it's gone bad they go opposite directions. Hope this helps.

 

Sorry SKYWARRIOR but that's not completely true. The donut will not really tell you anything about the state of the posi. Since the posi will somewhat unlock to allow the wheels to turn at different rates. Find a nice piece of light colored concrete, either do a sudden take off or a brake stand. If you got two even rubber stripes posi is displacing power to both wheels. If not then it's time to replace or repair. But are you sure that it is a posi/limited slip equipped car?
Hope I helped

 

Well .. I am not 100% sure but the RPO's say its a Limited Slip Differential... 3.27 9-Bolt Borg Warner Rear End... I have to do some investigating on my own....first I have to crawl undeneath her and look for the axle stamps, I need to get both tires off the floor as well and spin the wheels....then I am going to have drain the fluid and replace it and add the additive


If it's a posi rear and I have both tires off the floor and spin one tire what will happen to the other tire? Will it spin in the same direction or the opposite? I am thinking in the same direction....what

I have every reason to believe that my rear is posi because she has 16" wheels, and rear disc brakes.... supposely the IROC's in 87 that had the "performance rears" were equipped with posi rear axles. But I suppose all of that could have been faked....but I doubt it....

I will know more once I get the wheels off the ground and the inspection cover off.

 

I have the same rearend. If you look up the rpo on this site it will tell you if its positraction or not. Mine is posi. If youhave a haynes manual, and the little stamped tag still on your differential housing then you'll be able to tell. there is a section in the back of the haynes manual that has all the numbers. Oh, and one more thing. Sky knows donuts!

 

If you do have a 9 bolt, jack up one tire and measure the torque required to rotate the wheel. It should be at least 36 ft lbs, otherwise the posi is gone.

New series 3 posi units (and lots of other stuff) are available at www.9bolt.com

Miles

 

I sent you an email bud!! Did you get it?

I sent it to info@9bolt.com and info@diffsolutions.com

 

Good News!!

Well...for one I definitely know that my rear end is a Borg Warner 3.27 9-bolt posi!!! I jacked my car up tonight and pulled the inspection cover. Man was the diff. fluid black!!! Holy crap was it black!! Well actually sorta dark gray.

Anyway...the tag on the differnential cover stated " Limited Slip Differential"... humm no that wasn't it it was something that implied posi-traction...can't remember. Anyway I spun the driver's side wheel "while in Park" and the passenger side wheel spun as well... then I held the passenger side wheel and he could not spin the drivers side..it wouldn't spin at all. We did the reverse and the same thing! This is a good thing!!

So I got him to spin the wheel with the tranny in Neutral and I observed the pinion and ring gear turning...as the ring gear turned I noticed a marking on it...it read " BW 00 3.27"

So with all of this done I cleaned up the cover and diff. mating surface and bolted it back together with a new gasket (after I mucked out all of the old gear oil) I then added a bottle of the GM posi addditive and continued to top it off with some fresh synthetic gear oil...

All topped up and ready to roll....I never tried a burn out and likely won't :devil: well maybe sometime in the future .... but I certainly noticed a difference in the way she pulled...maybe it was just me but it feels like she is pulling harder now! Could be my imagination but I am sure that when I was on the highway and nailed it she bit harder and pulled harder... I dunno...

All I know is that I am a happy IROC owner again ... maybe the posi is weaker than it was originally but from what I saw tonight it is far from shot!!!

Thanks for all the tips and help guys

 

Unless you sent it from a different email address, I didn't get it. Try sending it to miles@koolmeister.com

Miles

 

Ok...now I have an answer that I am happy with

Took my car lunch time and rolled to a stop sign.. full straight away in front of me...so I say to myself... " OK car if your posi is f*cked you will only lay one strip of rubber...if its good you should lay down two strips" ... so I come to complete stop, got the rpm's up to around 1000, let the brake go and stomped on it.... tires screamed, she went sideways on me a little, and as I let off I look back.....

TWO BEAUTIFUL EVEN LENGTH BLACK STRIPES!!! Yeah baby!! HELL YEAH!!! Two nice stripes right through the painted white lines on the road!! hehehehe..

Now I know people have said... "An open ended rear can do that to...." But the pavement was bone dry and I doubt an open rear end would lay down rubber like that!!!

Posi shot?? I don't think so.... and all I did was change the gear oil and add a bottle of the GM Limited Slip additive.... did that make the difference?? Don't know... all I know is that the posi isn't gone... and I am happy with that!!!

Now I have to take it easy....new rubber is on the back and 245/50/16 tires ain't cheap!! hehehee

 

Hey

I am pretty sure that my car has posi becuase when I do burnouts I have to strips. But sometimes I get a nasty pegleg burnout. The RPO code for my rear end is GU6. It was the 3.42 gears for the 1985. Is that rear end a posi or not. \

How much does it cost to fix a posi.