Transfer Case Diagnosis - Jeep 1987 Wrangler Workshop Manual

GEARBOXES
MODEL 231 TRANSFER CASE
TRANSFER CASE DIAGNOSIS
Condition Possible Cause Correction
TRANSFER
CASE
DIFFICULT TO
SHIFT OR WILL
NOT SHIFT INTO
DESIRED
RANGE
TRANSFER
CASE NOISY IN
ALL DRIVE
MODES
NOISY IN — OR
JUMPS OUT OF
FOUR WHEEL
DRIVE LOW
RANGE
LUBRICANT
LEAKING FROM
OUTPUT SHAFT
SEALS OR
FROM VENT
(1) Vehicle speed too great to
permit shifting.
(2) If vehicle was operated for
extended period in 4H mode on
dry paved surface, driveline
torque load may cause
difficulty.
(3) Transfer case external shift
linkage binding.
(4) Insufficient or incorrect
lubricant.
(5) Internal components binding,
worn or damaged.
(1) Insufficient or incorrect
lubricant.
(1) Transfer case not completely
engaged in 4L position.
(2) Shift linkage loose or binding.
(3) Range fork damaged, inserts
worn, or fork is binding on
shift rail.
(4) Low range gear worn or
damaged.
(1) Transfer case overfilled.
(2) Vent closed or restricted.
(3) Output shaft seals damaged or
installed incorrectly.
ABNORMAL
TIRE WEAR
(1) Extended operation on dry
hard surface (paved) roads in
4H range.
(1) Stop vehicle and shift into desired range.
Or reduce speed to 3-4 km/h (2-3 mph)
before attempting to shift.
(2) Stop vehicle, shift transmission to neutral,
shift transfer case to 2H mode and operate
vehicle in 2H on dry paved surfaces.
(3) Lubricate, repair or replace linkage, or
tighten loose components as necessary.
(4) Drain and refill to edge of fill hole with
Jeep Automatic Transmission Fluid or
equivalent labeled D E X R O N ® II only.
(5) Disassemble unit and replace worn or
damaged components as necessary.
(1) Drain and refill to edge of fill hole with
M E R C O N ® automatic transmission
fluid. Check for leaks and repair
if necessary.
Note: If unit is still noisy after drain and
refill, disassembly and inspection may
be required to locate source of noise.
(1) Stop vehicle, shift transfer case to Neutral,
then shift back into 4L position.
(2) Tighten, lubricate or repair linkage as
necessary.
(3) Disassemble unit and repair as necessary.
(4) Disassemble and repair as necessary.
(1) Drain to correct level.
(2) Clear or replace vent if necessary.
(3) Replace seals. Be sure seal lip faces
interior of case when installed. Also be
sure yoke seal surfaces are not scored or
nicked. Remove scores and nicks with fine
sandpaper or replace yoke(s) if
necessary.
(1) Operate in 2H on hard surface (paved)
roads.
101730A
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