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The
Select Trac
option on
the Jeep Cherokee
gets you the
New Process
NP 242 transfer
case. This
transfer case
gives the
following
operating
modes: 2wd,
4wd with the
center differential
open, 4wd
with the center
differential
locked, neutral,
and 4wd low
range (center
differential
locked).
The
addition of
a center differential
is the main
difference
between the
NP 242 and
the NP 231
or Command
Trac transfer
case. Without
a differential,
the 231 transfer
case offers
only part
time four
wheel drive
mode.
The
NP
242
transfer
case
Full
time
mode
opens
the
center
differential
allowing
the
front
and
rear
axles
to
rotate
at
different
speeds
while
still
being
linked
by
the
transfer
case.
The
end
with
the
least
traction
will
get
the
most
torque.
While
this
mode
may
have
some
disadvantages
off
road
where
a
wheel
may
loose
contact
with
the
ground,
it
has
the
advantage
of
being
usable
on
all
paved
surfaces.
Part
Time
mode
-
with
the
center
differential
locks
can
only
be
used
on
loose
or
slick
surfaces
with
out
possible
damage
to
the
transfer
case.
I
use
full
time
mode
on
wet
streets,
hard
packed
gravel
or
dirt,
some
snow
and
ice
situations
and
on
dry
pavement
when
full
acceleration
without
wheel
spin
is
desirable.
I
use
part
time
mode
on
loose
gravel,
dirt,
grass
and
any
off
road
situation.
I
use
Part
time
mode
when
RallyCross
racing
as
well.
I
use
low
range
for
more
control
in
off
road
situations
or
on
rough
gravel
roads
when
traveling
downhill
to
avoid
excessive
use
of
the
brakes.
I
also
often
use
low
range
when
positioning
my
trailer
or
other
towed
equipment
when
precision
placement
is
needed.
The
NP
242
transfer
case
can
be
switched
between
2wd
and
either
4wd
mode
at
any
speed
simply
by
moving
the
lever.
The
switch
to
low
range
must
be
made
at
very
low
speed
-
the
Jeep
manual
says
3
mph.
One
common
operating
problem
with
the
242
transfer
case
is
that
it
will
stick
in
4wd
even
if
the
lever
is
moved
to
2wd.
Internally,
moving
the
lever
loads
a
spring
which
then
applies
force
to
move
the
selector
fork.
If
the
gears
are
loaded
with
torque,
the
spring
will
not
have
enough
energy
to
move
the
sleeve
off
the
gears.
Once
torque
is
removed
from
the
gears,
the
spring
will
then
move
the
fork
and
slide
the
sleeve
of
the
gears.
Momentarily
lifting
your
foot
off
the
gas
will
often
unload
the
gears
enough
to
allow
the
spring
pressure
to
move
the
fork.
On
some
high
mileage
units,
a
wear
groove
will
form
on
the
sleeve
or
gear
causing
it
to
stick
longer
and
may
require
a
couple
of
changes
from
loaded
to
unloaded
to
get
the
sleeve
to
release
form
the
gear.
The
Jeep
NP
242
is
lubricated
with
Automatic
Transmission
fluid.
The
level
is
checked
by
removing
the
upper
of
the
two
large
plugs
on
the
back
of
the
case.
The
fluid
should
be
level
with
the
upper
plug.
The
NP
242
has
a
slip
yoke
on
the
tail
shaft.
If
the
drive
shaft
is
damaged
or
removed,
fluid
will
be
lost
out
the
tail
shaft.
Also
this
seal
is
important
to
maintain
in
good
condition
to
prevent
fluid
loss.
The
NP
242
is
a
very
versatile
transfer
case
and
is
my
choice
for
three
of
my
five
Jeeps.
The
full
time
selection
gets
frequent
use
in
all
of
them.
Mike
Strawbridge
is
the
owner
of
Straw
Solutions
Performance
Consulting
where
he
teaches
others
how
to
get
the
most
performance
out
of
their
business
process. http://www.mikestrawbridge.com
To
learn
how
to
get
the
most
performance
from
your
Jeep
Cherokee
see http://mikestrawbridge.com/jeep-cherokee-off-road.shtml
For
more
Jeep
adventures
see http://jgandsr.blogspot.com/
Article
Source: http://EzineArticles.com/?expert=Mike_Strawbridge |
