posi or not?

[camarorat]

I was working on the car (2002 camaro) the other night and while putting the rear tires back on I noticed that only one side was turning. According to the door code the car came with posi rear. I place the car in nutural (not running), blocked the one side whell so it couldn't turn and was able to turn the other. I put the car on the ground and power braked it and I left two dark black marks on the pavement.

Now am am an older guy and in the old cars you had a posi rear if you spun one wheel and the other spun in the same direction. If yu turned one wheell and the other didn't spin, or spun in the opposite direction you didn't have a posi.

Am I missing something with these new cars. I opened up the rear, but couldn't tell if it was posi or not. It looks like nothing from the 60's.

Went out and wire brushed the right axle tube and discovered some numbers. They are hard to read but they could be as follows: OB1 C 142 1 or OEL C 242 1. Anyone know what thes numbers are?

[WildBillyT]

Rat,

Older cars had clutch-style posis (like Eatons) where that posi test would work most of the time. Really cooked posis could act like open diffs- I know, I had one.

The late model cars got gear-style (Zexel-Torsen) or cone-style (Auburn) limited slip differentials if it was spec'd. To the best of my knowledge none of them got clutch type LSDs. Is the car you are talking about a Z28 or SS? Some of the V6 cars got an open diff I think.

I do not remember if the "posi test" works on ZT diffs, I don't think it does.

[alamantia]

torsens are worm gear drivin, therefore when on a jack stand each wheel will spin in a different directions.

[camarorat]

Thanks for the replies. After I found out that it was torsen/true track design I learned that the rear acts like an open rear when the wheel are free as soon as a wheel starts to loose traction it adjusts to send power to that wheel. Basically it's only a posi when it has to be.