Lockers:
OK, now we come to the fun stuff. There are two types of lockers out there: Automatic and Selectable (or Manually Operated).
Where lockers are different is that speed, not traction or resistance, is the operating principal. It doesn’t care a whit about traction. Unlike a Limited Slip it will try to turn both wheels no matter what the traction conditions are. For example if one wheel is up in the air the other will still turn, period.
Just locking both sides together to guarantee delivery of the power to both wheels might be great off road. Or get you down a drag strip faster. But it could just as easily get your truck bent or in a worst case scenario, get you killed on a snow or ice covered road if you’re not careful. In a turn an automatic locker will unlock as the outside tire is being pulled ahead by the ground. This allows it to retain traction with all four wheels in the turn. This unlocking can often be heard as a clicking or ratcheting sound in a slow speed turn, like in a parking lot.
The down side is that they always drive the inside wheel or slower wheel in a turn. It can become a bit of a problem for someone not paying attention or inexperienced with it. Get a little too heavy with the gas pedal in a close parking lot, and your liable to regret it, especially if there is snow or ice on the ground. As long as the inside, driven, tire has enough traction to handle the power, all's well and good. If it can't then it will begin to slip, no surprise there. But the locker mechanism will only allow the tire to rotate a few degrees before it catches up with the outer tire. When that happens, there will be a sudden shock to the outer tire as the teeth in it lock up.
Now if you have gotten a little too frisky with the gas it can be rough. It can sound or feel like you might have broken something. Now things get interesting, the inner tire is now slipping so it is absorbing little or none of the engine output. It’s all suddenly dropped on to the outer tire. Kind of like sidestepping the clutch, hence its bad habit of snapping loose and sliding sideways. If that occurs and you still have your foot on the gas, like it or not, you’re going sideways. If this happens in the cramped quarters of a snow covered parking lot. It could very well mean an unplanned trip to a body shop. So on the street, and especially in close quarters a locker needs to be treated with certain degree of respect where the gas pedal is concerned.
push of a button becomes a spool (described below). Their big advantage is that they don’t have the odd handling characteristics of an automatic locker when turned “off” (open) for street use. But will provide the traction of a fully locked spool when engaged. You only need to “select” it as or when you actually want, or need it. Some newer selectable lockers are available today that combine a limited-slip function with a spool, rather than open/spool.
A Selectable locker is a different breed of cat. It’s actually two differentials in one. It ordinarily operates as an open, but with the push of a button becomes a spool (described below). Their big advantage is that they don’t have the odd handling characteristics of an automatic locker when turned “off” (open) for street use. But will provide the traction of a fully locked spool when engaged. You only need to “select” it as or when you actually want, or need it. Some newer selectable lockers are available today that combine a limited-slip function with a spool, rather than open/spool.
Selectable lockers usually cost a bit more money than automatic lockers, especially in the case of air lockers like the ARB. These require an added piece of equipment in the form of a compressor to operate them and require a driver input (the pushing of the button) to operate.
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