Hi i have a 1991 convertible trans am LB9 350 TBI car,

it seems like i have a limited slip rear end,

how can i get both wheels to spin from take off and while doing a burnout?

any tips tricks?

any besides wetting the road or p utting soap on the tires, or switching the rear end,


thanks,

Bob

 

Which is it? An LB9, a 350 or TBI?

If you have limited slip, spinning both wheels should be a non-issue.

 

it was a tpi car the ecm went bad and couldnt find another one for it for under gm pricing and so i converted it over to tbi, and yes its a 350 car,

i just cant seem to get the other wheen to spin... it will leave a 1 foot mark from take off then the passanger wheel steals its thunder

and sorry i meant L98 not LB9

 

A limited slip is a posi. If yours has a limited slip differential and it's only spinning one tire then it's worn out. My guess is you have an open differential. My


Mark.

 

Full depress the long skinny pedal on the right. I don't mean to be a smart ***, but that's how it's done.

If you don't have two black marks, then (1) you don't have a limited slip differential, or (2) your limited slip[ differential is not functioning properly.

Which reminds me... I haven't tested mine out in a week or so. Better get that done.

 

Perhaps you should pull the cover and take a peek.

JamesC

 

Block the front wheels, jack up the rear wheels then put jack stands under the rear, put the car in neutral then spin one tire with your hand , if the other tire spins the same direction then its a LSD if the other wheel spins the other way or not at all then its an an open diff.


Mark.

 

No need to remove the cover and make a mess. Jack up the rear end. Put trans in neurtral emergency brake off. Spin one wheel. If the other wheel spins in the same direction it's limited slip, If it rotates in the opposite direction it's an standard differetial.

I'm not sure about converable FB's, but Camaro's weren't available with the 5.7L. And since it's an auto and not a manual then it's probably a standard diff and not limited slip (posi).

The RPO for posi is C80 I believe. Are the FB's RPO codes in the rear hatch area?

 

G80 is the code for Limited slip. My codes are under the console cover.

Mark.

 

Your's is an 84, my 91 is in the rear hatch area.

 

mine must be a open diff then, ive jacked mine up and done that before... so now that thats out of the way how can i get them both to spin? and my car wasnt a factory 350 car i had it put in by gm after my 305 started knocking.. so its factory to me,

ive gotten both wheels to spin before, just dont know how i did it

 

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well it was a 305 tbi car, then i converted it to 305 tpi, the tpi ecm went bad and i didnt feel like paying a ton for another one plus the motor was knocking, so i had a 350 put in it by GM so it looks 100% factory, and i had them turn it back into a tbi car for it to look more original, heres a video

http://www.youtube.com/watch?v=zqgwLWX_mW0

 

Yea. I was just saying mine was there. It's all good.


Mark.

 

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Not necessarily. Note the "OR" below.

Do I Have a Limited Slip (aka Posi) (RPO G80*)?
Jerk the diff cover.** Open/Standard can be seen in the following link: https://www.thirdgen.org/forums/tr...1073-posi.html (posi?)

Gov-loc: https://www.thirdgen.org/forums/tr...rear-diff.html (3rd gen rear diff help!!)

Auburn: https://www.thirdgen.org/forums/tr...ing-axles.html (Tips/Tricks for Installing Axles, Bearings, Seals)

*Apparently, G80 was an extra-cost option which could be special ordered on any rear regardless of ratio.

**The most reliable way to determine if your car is equipped with a limited slip is to look. That said, this from big gear head: With the tires off the ground and the transmission in neutral, you should be able to turn one wheel and the other will follow in the same direction. This is limited slip or "posi". If the wheels turn in opposite directions, it’s a standard/open differential—OR a worn out limited slip.

JamesC

 

its a standard or worn out diff, the wheels spin different ways,

 

can i put a posi setup into my current rear end? or would it cause more problems then as if i were to just drop the axle and bolt a posi in its place?

what would that involve and could it be done right in just a few hours or would it take days?

 

If it has the standard clutch pack limited slip, and the clutches are worn out on one side both tires won't spin or the worn one will spin slower than the other. If both clutches are worn the car isn't going anywhere. I rebuilt quite a few of the jeep cherokee's in Kuwait that were worn out and towed in. All were clutch type.
And if you jack up just one side with trans in Neutral, that wheel will spin even with the other on the ground. If it's a standard it won't spin. (CORRECTION) It will still spin.

 

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your car appears to be a Firebird convertible, not a Trans Am since you are lacking the correct rear tail lights.

these are the lights you are supposed to have on your car if it was a Trans Am and you are in the US.

 

If you have a worn out Auburn limited slip then it's trash and can not be rebuilt. If you have a Governor Lock limited slip then it could be broke. It can be fixed, but it's not worth the trouble. The ONLY way to know what you have is to remove the cover and look inside. ALL other methods can fool you.

It's a shame that GM didn't install the Eaton Posi in these cars (along with the 8.5 rear end). You can install a Eaton Posi in your rear end as long as you have a 3.23 to 4.10 gear. The Eaton is only available in a 3 series, which will not fit 3.08 to 2.41 gears. Here is how to install it. http://www.nastyz28.com/forum/showthread.php?t=19773

 

Not if you use the same ring gear. You can install a new carrier with the same ring and make sure to put the spacers back the way they came. If you change gears, that's when you have to reset the depth and backlash and preload.

 

If this thread was a discussion about limited slip diff's in general or someone had an aftermarket, or non-stock diff/axle, yes, I agree. But it's about a specific car that by the owners posts we all can tell he has the 10 bolt standard stock rear end that could be a stock factory "posi".
If a car comes in to a shop with a complaint of an off idle hesitation, does the mechanic do a "tune-up" first. Maybe a mechanic does....but a technician would drive the car first and verify the complaint, not dissassemble it. If there was a flow chart to check for this, the first thing on the flow chart would be to spin the tires.

 

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Not if you use the same gears. ONLY when a different ring and pinion gear are used. And you have to change both together, you can't reuse say, the pinion, and change the ring. Must change both. BUT!!!!! when reusing both the ring and the pinion in the same housing and replacing with the same style carrier, you do not have to change anything. If that was true, you would also have to re-due pinion depth cause that's gonna change, by your statements.

 

1991L98G92 I,ve probably built more rear ends than the number of times you've been kissed. I've been there and done that. I've been the fool who bought a rear end after turning one axle and the other axle turned the same way. Then when I got back to my shop I removed the cover to find out that it was a standard differential and one of the axle tubes was bent causing it to lock the gears in the differential and turn both axles together. I've also bought rear ends that had been abused so much that the pinion gears were welded to the cross shaft causing both axles to turn together. On the other side I've almost passed up 12 bolt Chevy rear ends that turned the axles in opposite directions. I thought they had standard differentials in them, only to find out that the clutches were worn. I know what I'm talking about. If you want to be the fool who goes around turning axles and buying worn out junk thinking that it's something that it's not then go ahead. I'm just trying to keep bobbyk3lly from making a mistake by taking your bad advice.

By the way, where did you come up with this crap? This is TOTAL BS. "If it has the standard clutch pack limited slip, and the clutches are worn out on one side both tires won't spin or the worn one will spin slower than the other. If both clutches are worn the car isn't going anywhere."

 

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That's correct.

 

Correct - well put

 

OK so I read the forums. I have a 91 RS Camaro. Ive done a burnout out before, wasn't a real long on at all and both tires were spinning. I went up the road and did a long burnout but only one of my ties were spinning. The right side is the only one that spins when ever I do a burn out.


I'm not sure what rear end I have. All I know is that the car is pretty much all stock. Only that has been done to it was the guy before me had it tuned by some professional racers. So how exactly do I get both tires spinning?

 

The car would have originally been equipped with a 10-bolt. For a ton of info about the rear, check the following sticky:

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

JamesC

 

Go back and read post number 22. That is where you need to start. Until you find out exactly what you have there is nothing else that you can do.


Also, you probably should have started a new thread instead of tacking onto this one.