I've been meaning to ask this question for some time: What exactly is a locker? Is it the same as posi-trac?
Say you've got a rear wheel drive truck whose differential has posi-trac. Wouldn't that mean that power is going to both rear wheels in equal amounts at all times? Can a locker be controlled by the driver? In other words, if it can, wouldn't it be like posi-trac on demand?
If I'm asking ******** questions it's because I simply don't know a whole lot about differentials.
You're on the right track. I'm not sure about the difference between a "posi" rear-end versus a limited-slip, but I can tell you a limited slip uses friction or torque clutches to attempt to make both wheels spin. Limited slips can still only direct power to one of the two wheels, when the amount of force from the drive-train exceeds the amount of friction that is attempting to force both rear wheels to spin.
Lockers do just that....they lock both rear axles together within the differential. There are automatic lockers (Powertrax, Aussie, for example) then there are air lockers (ARB).
Auto-lockers work by allowing one wheel to spin faster than the other as long as there isn't an excessive amount of force being applied by the drive-train. For instance when going through a turn, you usually let off the gas a bit, coast thru, then apply force to accelerate out of the turn. The locker will allow one wheel to go faster thru the turn, but then as you come out of the turn and force is reapplied, the locker will re-engage.
Air lockers are controlled by the driver...you are either locked or you are not. You have to have an air-source (onboard compressor, storage tank, plumbing) and this goes to the locker. When you apply air pressure, the locker engages, and will stay engaged until air pressure is released.
Make sense?
