If you're concerned, checking your personal limited-slip diff is simple:
jack up a rear wheel, attach a torque wrench to a nut and torque until the wheel
breaks loose. A new std ZF diff will be about 45 ft-lbs; a 'tight' ZF
diff will be around 75 ft-lbs, give-or-take. This checks the clutch pack on that
axle; to be thorough, do the other wheel. A big difference can mean one disc or
plate is bad on that axle. GM used to check random cars off the assembly line by wetting & soaping a section of concrete floor, then putting a 2x4 in
front of one tire. If the car could climb the board, the LSD on that side was set about right. Finally, since ZFs use a posiâ„¢-type LSD, using posiâ„¢-type
rear end lube may cure jerking around corners in the wet, as is common with clutch-type diffs.
Cheers- J Deryke