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Lunch Box Lockers, Full Lockers, Spools, Limited Slips,
Positraction, Lincoln Lockers, and Open Diffs. You've heard the words, but
what does it all mean?
| It all has to do with how your rigs power gets put
to the ground through the differential in the axles. The most common
setup from the factory is an open differential. This is a street
friendly setup that puts power to the tire with the least amount of
traction. This makes cornering on the street easy and makes your
tires last longer. However in an off road situation where one tire
gets lifted, it will be the one that will spin and you will go
nowhere fast. There are a few ways to tackle this problem, all with
their own pros and cons. |
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Limited Slip or Posi Trac-
A Limited Slip or Posi Trac is the same thing. There are
clutches inside the differential that allows power to be transferred
to both tires at the same time. There are different approaches to
this as the clutches can be in different locations or some other
type of torque transfers system is used. What is all boils down to
is that some power will be sent over to the tire with the most
traction. This power transfer can range from low like 30% to up to
90% or more. However all power will not be transferred as the design
is supposed to allow some slippage. This is so that the vehicle will
still remain street friendly and tight turns will be easier on the
drive train. This is an option on performance cars and on some
trucks. These can make a real difference in the performance of your
rig and it is very common to find them up in the front diff so
steering is still reasonable but traction is improved. Look at the
picture on the left and you can see the springs in the center that
apply pressure to the clutches. The harder the spring, the more
torque transfer. |
Automatic Lockers- An
automatic locker applies 100% of the torque transfer to both tires but
will allow the wheels to disengage for some street manners. But here's the
trick, a locker will allow one wheel to spin faster then the driven
wheel. This means that when accelerating around a corner, the locker
will drive the inside tire and will allow the outside tire to ratchet
ahead. This will try to force you strait when on the throttle in a corner.
If you coast the corner it will behave fine. When both wheels are turning
at the same speed it will lock back up. This locking and allowing one tire
to turn faster then the driven tire can make some good popping noises on
new lockers. Once they wear in, they usually shut up. Pro's are they work
great. Cons are they can break on you.
Lunch Box Lockers- A lunch
box locker is an automatic locker that replaces only the spider gears.
These are the four little gears in the center that allow the tire with
traction to not move when you need it to. You can install these in the
driveway without pulling the carrier or resetting up the gears. Its one of
the most popular options for its ease of installation and usually they are
not too expensive. Lock Rite and Detroit offer these type of lockers. Also
Aussie and Quick loc offer their own versions. Below is an exploded view
of a lunch box locker. Pro's are that anybody can put one in. Cons are
they are the weakest type of locker and big tires can kill them.
| Full Carrier Lockers- A
full carrier locker is an automatic locker that also replaces the
carrier for the ring gear with a stronger version and houses the
locker itself. The only one worth mentioning is the Detroit Locker.
This was first designed for the military and is available in many
applications. Pro's are is very strong and Cons are it is expensive
and you have to set up the gears again as the carrier is changed
out. |
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Spools- A spools replaces
the spider gears and connects both axles together for full power to
both tires all the time. There are two kinds. A mini spool (left) that
just replaces the spider gears, and a Full spool (right) that replaces
the carrier. A spool is great for the most extreme type of wheeling.
Pro's are they are cheap and the mini spool is easy to put in plus
100% power to both wheels all the time. Cons are bad handling on the
street and can be difficult to turn. This can be hard on axles and
tires. |
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User Controlled Lockers- A
user controlled locker is a locker that the driver can engage and
disengage at will. There are several different kinds and the most popular
kinds are the Air Locker, the Electric Locker and the Cable Actuated
Locker.
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Air Lockers- An Air
locker is a locker that is actuated by air pressure delivered through
an air line routed into the differential housing. The only real player
in this market is the ARB air locker. The Pros are a good locker with
control at the push of a button. The Cons are you will need an air
source to run it (ARB sells a compressor for it) and the air lines can
be a maintenance issue. |
| Electric Lockers- An
Electric Locker is the same as an Air Locker but instead of air, it
just needs a power source to lock it in. There are a couple of
different versions. Some are Limited Slips when off and some are open
when off. This type of locker has come in stock Toyota's for years. Aftermarket versions are available from Eaton,
and Auburn and maybe elsewhere. Pro's include easy to wire and to use.
Cons include cost and availability and installation. |
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Cable Actuated
Locker- The only real cable actuated locker on the market is
the OX Locker. This locker works like the above but a cable and handle
assembly that is mounted in the cab is used to engage and disengage the
locker. Pro's and a solid shift that you know is locked, Cons are it can
be hard to lock in while bound up and cost and installation. |
| Lincoln Locker- A Lincoln
Locker is a spool that is made by welding the spider gears up in the
housing to create a permanent spool. It has that name because you can use
your Lincoln Arc welder to do it. Pros are you can do it for the price of
the rod and in your driveway. Cons are you now have a permanent spool
which might be fine for a rig. |
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Planet 4x4 |
