Posi Rear Issues

QUESTION: Stellios Pantelaras asks: I have a 1988 Iroc-Z, it has the stock GM 10 bolt 2.73 posi rear. Well the definition of posi is that both rear tires have power, well mine only one tire has power at a time. I was told the clutches in the limited slip are worn and need replacing. What is the kit to do that called and where (other than dealer as dealer will cost me an arm and a leg) can I get this stuff.

CHECKING POSI OPERATION: Do this first, as certain conditions may affect how the posi operates:

1. Raise both rear wheels off of the ground and place transmission into
'park,' or 'reverse' gear for manual trans. cars.

2. Check the rotational torque by rotating 'one' wheel. There should be a min. of 125 lb/ft to up to 225 lb/ft of resistive torque (should be very hard to
rotate the tire by hand-but check with a 'torque wrench,' place, perhaps, onto one of the lug nuts (be sure to check to see if the nut becomes loose or over tightened after doing this!!) At this point, the driveshaft should be 'locked' and not moving because of being in park or in reverse gear(manual trans.).

3. Now lower one wheel onto the ground, with the transmission in 'neutral
(driveshaft allowed to turn'). Rotate the raised wheel and measure from 45 to 100 lb/ft. of torque resistance.

4. If the above conditions are not met. then the entire 'chuck' must be
replaced (about $512.00 from the dealership (includes: Ring & Pinion gears
with posi differential) GM does not sell the posi differential carrier as a
separate unit. However, you may be able to buy a new Auburn posi differential for $290.00. You must double check to see if they still make a unit for 2.73:1 but they are a OEM (original equipment manufacturer). This is still an expensive proposition, as the Ring and Pinion gear must be properly 'lashed,' and if not done 'perfectly,' the whole thing will have to be replace in less than 10,000 miles! All bearings, seals, et. are extra. A typical rebuild is close to $2,000.00. And, there is no cheap way to get around it. You could buy a used axle from a trashed 4rth gen car, in the NE, an 11Kmile '96 unit is between $700-800.00, figure another $200.00 for fresh axle end bearings, seals, lube, cover gasket...and another $150-200.00 to install it. You might save $600-800.00 going this route, but, if the car it came from was really hammered badly, especially in the back, there could be internal damage no one can see. They your cost could go above a re-build. And if you do go for a rebuild, you might as well go for a 3.42 or 3.73:1 gear set. The 2.73:1 is just to 'economy' for a sports car.