# Posi?



## THEHERDER (Aug 3, 2005)

My 05 GTO will burn both tires if I'm going straight, however if I try and burn both tires at a U-turn, the car is the one wheeled wonder. It only burns the inside tire ande I hate it. What do I do?


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## Guest (Aug 4, 2005)

Don't try to burn both tires at a U-turn.


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## EEZ GOAT (Jul 9, 2005)

THEHERDER said:


> My 05 GTO will burn both tires if I'm going straight, however if I try and burn both tires at a U-turn, the car is the one wheeled wonder. It only burns the inside tire ande I hate it. What do I do?


if u got the money to buy two or four tires every month or two, go for it :cheers


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## JMVorbeck (Jun 1, 2005)

THEHERDER said:


> My 05 GTO will burn both tires if I'm going straight, however if I try and burn both tires at a U-turn, the car is the one wheeled wonder. It only burns the inside tire ande I hate it. What do I do?


Because the GTO does not have POSI, it has a DANA clutch type limited slip differential. The clutch pack is only engaged when both wheels are traveling at the same speed, essentially producing a "Positraction" type locked differential. However, when one wheel needs to increase speed over another as in a corner (the outboard wheel needs to spin faster) the clutch pack disengages and the differential behaves as a conventional differential would. So what you are finding is perfectly normal. If you locked the differential full-time, as in a POSI rear end, you would seriously compromise your daily drivability as every time you went around a corner your tires would squeel and scrub against the pavement. I just dropped coin on a new set of rear tires a 6000 miles, trust me, the last thing you want is more tire wear than 400 horses already induces. :cheers


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## THEHERDER (Aug 3, 2005)

The rear end limited slip is horrible, I had a Z06 and it could burn tire any time I wanted. I am very bitter that my GTO cannot do a donut


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## Punchy (May 11, 2005)

You apparently have more money than I do. You`ll be one of the first to bitch about GM when you blow the rearend up..............have a ball


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## jcain (Aug 9, 2005)

idiot...


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## JMVorbeck (Jun 1, 2005)

THEHERDER said:


> The rear end limited slip is horrible, I had a Z06 and it could burn tire any time I wanted. I am very bitter that my GTO cannot do a donut


HERDER, you cannot do a donut? Sliding the ass end around is very easy. Start off straight, get your tires spinning and then turn your wheel. You will be 360 degrees before you know what happened. Trust me, its eaiser than you think, I have dont it on accident before in a U-Turn in a lot.


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## JMVorbeck (Jun 1, 2005)

jcain said:


> idiot...


There is no need for name calling. If the guy wants to flip a donut in his car, its really none of your business. Didnt your mother ever tell you "If you dont have something nice to say, dont say anything"?


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## THEHERDER (Aug 3, 2005)

Thanks JM, I was just used to the Vette. Don.t get me wrong, Ilove my GTO. I was just a little disapointed in the limited slip. I expected it to pull both tires anytime I wanted and I just want to make sure nothing is wrong with the rear in the car.


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## mumrah (Apr 3, 2005)

I plan to upgrade the stock cheapo tires soon anyway so I am having fun burning rubber, no sense in getting rid of tires with alot of tread. I have done donuts in my GTO several times. in the beginning I was leaving twin circles when both wheels were spinning but now as the car is breaking in I noticed that sometimes one wheel does not. i know that this is normal for a limited slip but I liked it in the beginning when things were so tight it almost felt like a locked diff. I also have a backup set of stock wheels with like new tires just waiting. I wanted a set of stock wheels so I could just interchange the rears with DR's to Summer/Rain tires and back to the stock for light winter without having to remount the tires. New rear tires are alot cheaper than one of those speeding tickets at over 100 or even worse getting caught street racing.


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## JMVorbeck (Jun 1, 2005)

mumrah said:


> I plan to upgrade the stock cheapo tires soon anyway so I am having fun burning rubber, no sense in getting rid of tires with alot of tread. I have done donuts in my GTO several times. *in the beginning I was leaving twin circles when both wheels were spinning but now as the car is breaking in I noticed that sometimes one wheel does not.* i know that this is normal for a limited slip but I liked it in the beginning when things were so tight it almost felt like a locked diff. I also have a backup set of stock wheels with like new tires just waiting. I wanted a set of stock wheels so I could just interchange the rears with DR's to Summer/Rain tires and back to the stock for light winter without having to remount the tires. New rear tires are alot cheaper than one of those speeding tickets at over 100 or even worse getting caught street racing.


That is interesting you mention that, I noticed the exact same thing! I wonder if the clutch packs in the diff get broken in and are not so tightly packed together. I liked it better before, it would bring the ass around alot faster before in a U-turn (We live by them here in FL), now I have to make it do it. I wonder if those DANA's ever need adjustment, to take up the wear slack in the LS clutches.


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## slowride (Sep 2, 2005)

JMVorbeck said:


> Because the GTO does not have POSI, it has a DANA clutch type limited slip differential. The clutch pack is only engaged when both wheels are traveling at the same speed, essentially producing a "Positraction" type locked differential. However, when one wheel needs to increase speed over another as in a corner (the outboard wheel needs to spin faster) the clutch pack disengages and the differential behaves as a conventional differential would. So what you are finding is perfectly normal. If you locked the differential full-time, as in a POSI rear end,



I had some questions on differentials, did a search and turned up this thread and this post.
Is this right?? :confused 

Posi is short for Posi-Traction, which is Chevrolet's trade name for a clutch-type limited slip differential. GM hasn't sold a true "locking" differential in decades.
A limited slip differential, such as the one in the GTO, will allow limited amounts of slip...just as the name implies.....when the force on the clutch plates becomes greater than the friction on those same plates. 
Manufacturing tolerances would mean some units will slip before other units would, but since it is meant to give traction on low-traction surfaces like ice, snow, mud, and other wet surfaces (and not provide every juvenile delinquent the means to lay two black stripes on dry pavement), no dealer would say a Posi-Trac that wouldn't lay rubber is faulty.
This is what I've read from reliable sources, like Factory Service Manuals, over the years. Was JMV confused or am I?

slo


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## SloTymer (Sep 16, 2005)

slowride said:


> I had some questions on differentials, did a search and turned up this thread and this post.
> Is this right?? :confused
> 
> Posi is short for Posi-Traction, which is Chevrolet's trade name for a clutch-type limited slip differential. GM hasn't sold a true "locking" differential in decades.
> ...


You are right, Posi-Track is the name for a limited slip diff. The other was actually called a Detriot-Locker, and it was a bitch when cornering and passing.


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## Russ Schaeffer (Jun 3, 2006)

The 4 common types of rear ends are:

1. Clutch type diffs:
Posi-Traction GM
Traction-Loc Ford
Sure-Grip Chrysler

2. Cone type: Auburn

3. Detroit type: with radial Splines (clicks when you turn)

4. Spool: always locked

The clutch types are the most subject to wear and will be less effective after being abused. You can tell if it's working if the rear end groans or the inside tire scrubs as you turn at low speeds. A rear end specialist can adjust your clutch pack to be more effective but a cone type limited slip is best for heavy street use. 
Thanx,
Russ

Oops I forgot the most common one. The "open" rear end where only one wheel is driven (the wheel with the least traction).


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## bg2m8o (Jul 25, 2006)

Dont forget the infamous TORSEN dif. (TORque SENsing


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## HADAWS6 (Dec 5, 2005)

Is That The Same As Jack Torse


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