Do I have Positraction

[DPOK]

We are changing the rear differential gasket and fluid and need to know if we need to put in the positraction fluid. If we are not in the position to do a burnout. Without dropping the driveshaft, is there a way to know if we have positraction and need the additive?

Thanks,
Dave

 

[camaro71/holland]

Get a bottle of additive, pop the cover. If it's a posi, add the bottle if not - don't.

If you have the time, just pull the cover and then get the bottle or not.

You never need to drop the DS to check the differential, just the cover.

 

[tom3]

For manual tranny. Jack up one wheel, transmission in neutral, turn the wheel. If you feel pretty serious drag it's probably a posi, if it spins freely it's not, or it's just worn out.

 

[COPO]

Simple, jack up the rear with both tires off the ground, put trans in neutral and turn one rear wheel by hand in one direction, if the opposite wheel spins in the same direction then you have posi.

 

[big gear head]

Remove the cover and look at it. If there are 4 gears in the center of the differential and nothing else then it's a standard differential. If it has a flat metal spring in the shape of a S, or 4 or 5 coil springs in the center then it's a limited slip differential and you need the additive.

 

[COPO]

This is my posi rear in my 70 Z28.

 

[Fbird]

Simple, jack up the rear with both tires off the ground, put trans in neutral and turn one rear wheel by hand in one direction, if the opposite wheel spins in the same direction then you have posi.

USUALLY....but this CAN be misleading at times as sometimes the spider gears will cause BOTH wheels to spin in the same direction!!!!....but NOT A POSI.
The more definitive approach is car in neutral, jack up 1 rear tire...try to rotate it (FWIW a GOOD posi requires about 60 ft/lbs torque to "break away" from clutch hold). If it rotates pretty easy...NOT A POSI.
THE DEFINITIVE WAY.... remove cover. Usually 4 springs (like COPO) or 1 "S" spring between the axle gears