Common definitions:

A limited-slip differential or “posi”, often shortened to LSD, is a traction aid that ensures that a tire on a low-grip surface won’t spin uselessly.  This can be done in many ways, typically it’s done with clutch discs and preload springs.  When one-wheel slips, the torque is transferred via the differential case through the clutches to the wheel that has less traction.

A G80 differential is a specialized differential designed by Eaton to work as a low-speed traction aid, offering full lockup during its operation. When in normal conditions, the unit acts as an open differential, letting the rear tires spin independently of each other, with the outside wheel spinning faster during turns.

Important thing to remember about a G80 is the phrase “low-speed traction aid” the G80 is NOT a high-performance differential.

Locking Differential Torque-Limiting “Fuse” Disc

The locking differential design was modified in mid-1986 to include a load-limiting feature to reduce the chance of breaking an axle shaft under abusive driving conditions.  We call this special disc the “fuse” disc.  The number of tangs on the fuse disc in the left-hand clutch pack was reduced allowing these tangs to shear in the event of a high-torque engagement of the differential locking mechanism.