4WHEELOFFROAD.COM 4-WHEEL & OFF-ROADNOVEMBER 2019 17
DIFFERENTIAL TYPE CASE STYLE ENGAGEMENT METHOD PROS CONS CHARACTERISTICS
Powertrax
Lock
Right
Mechanical
locking
differential
Drop in stock
case
Automatic Inexpensive. Easy
setup.
Stock differential
case is usually the
weak point.
Great way to test
the waters to see if
you really want to
upgrade to a full case
locker.
Strange
Engineering
Spool
Spool Full case
replacement
Always locked Inexpensive.
Simple, bulletproof
traction.
Not at all ideal
on-road. Tires
chirp when
cornering. Hard
on axleshafts and
other drivetrain
components.
Best used in the
rearend of 4x4s that
spend most of their
time off-road. Not for
front applications
where steering is
important.
USA Standard
Gear
Spartan
Locker
Mechanical
locking
differential
Drop in stock
case
Automatic Inexpensive. Easy
setup.
Stock differential
case is usually the
weak point. Tire
size limitations.
Great way to test
the waters to see if
you really want to
upgrade to a full case
locker.
Yukon Dura Grip
Positraction
Clutch disc
limited slip
Full case
replacement
Automatic Nearly seamless
operation on the
street. Great for
on-road snow and
ice. Can be rebuilt
at home.
Provides
marginally better
traction than an
open differential.
Requires friction
modifier in oil.
Clutches wear out.
Best used on the
street and very mild
off-road applications.
Yukon Grizzly
Locker
Mechanical
locking
differential
Full case
replacement
Automatic Simple. No wires,
no air lines,
no switches,
no special oil
required.
Can cause on-road
handling quirks
and does not play
well with ABS and
other sensors
found on newer
4x4s.
Automatic locking
function can be a
bit brutish for some
drivers. Best used on
4x4s that spend a lot
of time off-road.
Yukon Mini
Spool
Spool Drop in stock
case
Always locked Very inexpensive.
Simple, easy
setup.
Very limited
applications.
Stock differential
case is usually the
weak point.
Best used in the
rearend of 4x4s that
spend most of their
time off-road. Not for
front applications
where steering is
important.
Yukon Spool Spool Full case
replacement
Always locked Inexpensive.
Simple, bulletproof
traction.
Not at all ideal
on-road. Tires
chirp when
cornering. Hard
on axleshafts and
other drivetrain
components.
Best used in the
rearend of 4x4s that
spend most of their
time off-road. Not for
front applications
where steering is
important.
Yukon Zip Locker Mechanical
locking
differential
Full case
replacement
Selectable, internal air
engagement
Benefits of open
differential when
unlocked.
Requires air
source. Air lines
are fragile. Internal
air leaks will case
it not to function.
Cannot be
manually operated
in an emergency.
Engages and
disengages quickly.
Great choice for front
differentials and
front and rear in daily
driven 4x4s.
SOURCES
ARB
866.293.
arbusa.com
AUBURN GEAR
260.925.
auburngear.com
EATON
800.328.
eaton.com
G2 AXLE & GEAR
310.900.
g2axle.com
OX USA
727.230.
ox-usa.com
POWERTRAX
800.934.
powertrax.com
SPICER PARTS
800.621.
spicerparts.com
STRANGE ENGINEERING
847.663.
strangeengineering.net
TORQ-MASTERS
585.723.
torqmasters.com
USA STANDARD GEAR
usastandardgear.com
YUKON GEAR & AXLE
888.905.
yukongear.com