On the earlier, like '50s+ GM PTrac units, they were "locked until they unlock" The four springs kept the frictions "solid" all of the time. No engagement cams, just friction lock. The "unlock" happened when the rear wheels each had a different rotational speed, as in tight corners. This is when they'd pop as the frictions slipped. The special lube and/or additive was required. As things progressed into the 1980s, the 4 springs were replaced by a flat S-shaped spring. These were all "GM PosiTraction Limited Slip", option code G80 differentials. I believe that Ford and Chrysler used similar units, similar in design and action.
In the 1990s, GM started to use a "locker" (NOT Detroit locker!) differential. I was "unlocked until it locked". The locking action happened when wheel speed was different enough to swing a governor counterweight outward to engage a thin gear and "lock" the differential. Then, there was also an "inhibit" mechanism to unlock the locked differential when wheel speed was great enough, like highway speed. So the locking action was only at lower speeds. Initially, these axles needed no special lubes (as most lubes were now universal in nature), but the old PTrac Additive was later added-in with particular vehicle applications. By the time this was going on, all Chrysler had that was rwd was light trucks.
As I recall, the Detroit Locker and others like it did use "cams" to engage the locking action and/or clutches. I also recall reading the info about the weaknesses or the cone clutch limited slip units, too. But all of the earlier GM PTracs I've known about were spring loaded "locked until they unlock" designs.
The SLP Firebirds used an Auburn limited slip differential. When discussing some issues with one of them (read from an online forum on such), my performance mechanic associate/drag racer noted that there were different levels of Auburn differentials. And that the ones used in the Firebirds was their "lowest line" unit. I believe he said there were THREE different lines of those differentials and that the upper two lines were pretty decent items. For THIS reason, further investigation might be in order of WHICH Auburn differential is what. Not "generic", it appears.
In order to decrease failure rates, my recommendation is always to look at what the OEMs use as their optional items. This ensures that most mechanics will know what they are looking at and can then intelligently order parts, if needed. Getting into the aftermarket can be problematic in these areas, by observation. Sometimes, that "cheesy factory stuff" will hold up better than that "upgrade performance" item, by observation. IF the OEM has issues with durability and longevity (in normal use), they tweak and improve it incrementally. IF the aftermarket has problems, that part tends to disappear for a while, to possibly resurface somewhere else in a different time. In the mean time, if the first company went broke, somebody else might by marketing rights to it and start it over again. End result . . . the consumer ends up holding the bag of broke parts, usually. I first saw that Torsen-style axle advertised in the earlier 1960s. as an improvement over the factory OEM items of the time. Then little of it was seen (magazine ads and articles) until much later. BTAIM
CBODY67
In the 1990s, GM started to use a "locker" (NOT Detroit locker!) differential. I was "unlocked until it locked". The locking action happened when wheel speed was different enough to swing a governor counterweight outward to engage a thin gear and "lock" the differential. Then, there was also an "inhibit" mechanism to unlock the locked differential when wheel speed was great enough, like highway speed. So the locking action was only at lower speeds. Initially, these axles needed no special lubes (as most lubes were now universal in nature), but the old PTrac Additive was later added-in with particular vehicle applications. By the time this was going on, all Chrysler had that was rwd was light trucks.
As I recall, the Detroit Locker and others like it did use "cams" to engage the locking action and/or clutches. I also recall reading the info about the weaknesses or the cone clutch limited slip units, too. But all of the earlier GM PTracs I've known about were spring loaded "locked until they unlock" designs.
The SLP Firebirds used an Auburn limited slip differential. When discussing some issues with one of them (read from an online forum on such), my performance mechanic associate/drag racer noted that there were different levels of Auburn differentials. And that the ones used in the Firebirds was their "lowest line" unit. I believe he said there were THREE different lines of those differentials and that the upper two lines were pretty decent items. For THIS reason, further investigation might be in order of WHICH Auburn differential is what. Not "generic", it appears.
In order to decrease failure rates, my recommendation is always to look at what the OEMs use as their optional items. This ensures that most mechanics will know what they are looking at and can then intelligently order parts, if needed. Getting into the aftermarket can be problematic in these areas, by observation. Sometimes, that "cheesy factory stuff" will hold up better than that "upgrade performance" item, by observation. IF the OEM has issues with durability and longevity (in normal use), they tweak and improve it incrementally. IF the aftermarket has problems, that part tends to disappear for a while, to possibly resurface somewhere else in a different time. In the mean time, if the first company went broke, somebody else might by marketing rights to it and start it over again. End result . . . the consumer ends up holding the bag of broke parts, usually. I first saw that Torsen-style axle advertised in the earlier 1960s. as an improvement over the factory OEM items of the time. Then little of it was seen (magazine ads and articles) until much later. BTAIM
CBODY67
but now i don't know if i dare to do burnouts inte the future when I change from my open diff to the Auburn LSD?
