2) To determine if front axle has completed a shift out of
4WD into 2WD, position mode select switch back to "4WD" position while
operating vehicle at slow speed. If vehicle shifts into 2WD, axle will
ratchet. If shift is not completed, transfer case will shift into 4WD
and hissing sound will come from mode select switch.
FRONT AXLE SHIFT MOTOR TEST
1) Disconnect vacuum harness from front axle shift motor.
Connect vacuum pump to shift motor front port. Apply 15 in. Hg vacuum
to shift motor. Rotate right front wheel to disengage axle.
2) Shift motor should hold vacuum at least 30 seconds. If
not, replace motor. If motor does hold vacuum, disconnect vacuum pump
from shift motor front port. Connect pump to shift motor rear port and
cap transfer case connecting port. Apply 15 in. Hg vacuum to motor.
3) Shift motor should hold vacuum for at least 30 seconds. If
not, replace motor. If motor does hold vacuum, remove cap from shift
motor transfer case connecting port and check for vacuum. If no vacuum
is present, rotate right front wheel to ensure axle has shifted
completely. Axle must completely shift to open shift motor connecting
port.
4) Recheck vacuum at shift motor transfer case port. If
vacuum is present, transfer case requires diagnosis. Command-Trac uses
Model 207 transfer case. Selec-Trac uses Model 228 transfer case.
REMOVAL & INSTALLATION
LOCKING HUB
Removal
1) Remove cover to outer clutch housing. Remove bearing race
spring assembly. Remove sealing ring and seal bridge retainer. Remove
bearing components.
2) Squeeze tangs of wire retaining ring together with needle-
nose pliers. Pull remaining components of automatic hub from wheel.
Installation
1) Ensure lock ring is in position. Using Bearing Nut Wrench
(J-6893-D), tighten wheel bearing adjusting nut to 50 ft. lbs. (60 N.\
m) to seat bearings.
2) Back off nut and tighten to 35 ft. lbs. (47 N.m) while
rotating hub. Finally, back off nut a maximum of 3/8 turn. Assemble
lock ring (with tab in keyway) over axle shaft, against bearing
adjustment nut.
3) Adjustment nut pin must pass through one of the washer
holes. Tighten outer adjusting nut to 183 ft. lbs. (248 N.m). Align
outer clutch housing splines with splines of wheel hub.
4) Loosen cover screws 3 or 4 turns, and push in on cover to
allow retaining ring to expand into rotor hub groove. Tighten cover
cap screws to 40-50 INCH lbs. (4.5-5.6 N.m).
Fig. 2: Selec-Trac Vacuum Control System
AXLE SHIFT MOTOR & HOUSING
Fig. 1: Exploded View of Saginaw Rotary Valve Power Steering Gear
ADJUSTMENTS
THRUST BEARING PRELOAD ADJUSTMENT
1) Remove steering gear from vehicle. Remove adjuster plug
lock nut. Turn adjuster plug clockwise with a spanner wrench until
plug is seated in housing. This will require 20-30 ft. lbs. (27-41 N.
m) of torque.
2) Place an index mark on housing opposite one spanner wrench
hole in adjuster plug. Measure 1/2" (13 mm) counterclockwise from mark\
and again mark housing. Rotate plug counterclockwise until hole in
adjuster lines up with second mark.
3) Tighten lock nut. Ensure adjuster remains in position.
Attach an INCH lb. torque wrench to end of input shaft. Turn input
shaft to right stop, then back 1/4 turn.
4) Using torque wrench measure rotational torque required to
turn shaft. Reading should be taken with beam of torque wrench near
vertical while turning it counterclockwise at an even rate. Torque
reading should be 4-10 INCH lbs. (.4-1.1 N.m). See. Fig. 2.
NOTE: All other models are not adjustable.
BALL JOINTS
Jeep, Truck & Wagoneer
1) Raise vehicle and remove front wheels. Disconnect
steering damper and connecting rod. Remove cotter pin from right side
tie rod retaining nut. Rotate steering knuckles through complete arc
several times.
2) Place torque wrench on right side tie rod retaining nut.
Torque to turn knuckles through complete arc should not be more than
25 ft. lbs. (34 N.m).
3) If turning effort is excessive, disconnect tie rod ends
at knuckles. Measure turning effort of right and left side knuckles.
Individual turning effort should not be more than 10 ft. lbs. (14
N.m).
4) If individual turning effort is more than specified,
replace upper ball joint split ring seat. If turning effort is more
than 10 ft. lbs. (14 N.m) after split ring seat replacement, ball
joints will have to be replaced.
TURNING ANGLE
Truck & Wagoneer
1) Turning angle stop screws are located at rear of steering
knuckle, just above axle centerline. To adjust, loosen lock nut on
turning angle stop screw. Jeep turning angle is not adjustable.
2) Using turntable to measure angle, adjust stop screw to
obtain specified angle. Tighten lock nut without changing setting.
TURN ANGLE ADJUSTMENT
TURNING ANGLE ADJUSTMENT TABLE \
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Application Left Right
Wheel Wheel
Jeep
Cherokee,
Comanche,
& Wrangler .......... ( 1) 32-33
................. ( 1) 32-33
Wagoneer ................. 36-37 ....................... 36-37
(1) - Angle stops are not adjustable. Parts must be replaced if
angle is incorrect.
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TORQUE SPECIFICATIONS
TORQUE SPECIFICATIONS TABLE \
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Application Ft. Lbs.(N.m)\
Ball Joint Type
Lower Ball Joint Nut
Jeep .................................................. 100 (136)\
Upper Ball Joint Nut
Jeep .................................................. 100 (136)\
Upper Ball Joint Split Retaining Seat
Jeep ..................................................... 50 (68)\
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SU SPEN SIO N - F R O NT
1988 J e ep C hero ke e
1988 FRONT SUSPENSION
Jeep Coil & Leaf Spring
Cherokee, Comanche, Grand Wagoneer, Wagoneer, Wrangler
DESCRIPTION
Cherokee, Comanche and Wagoneer 2WD and 4WD front
suspensions consist of solid axle (tubular axle on 2WD), 4 control
arms, 2 coil springs and track bar. Track bar is used to minimize
front axle side-to-side movement. Stabilizer bar and shock absorbers
control suspension spring movement.
Grand Wagoneer and Wrangler models use leaf spring front
suspension with shock absorbers and stabilizer bar. Wrangler also uses
a track bar to maintain lateral position of front and rear axles.
ADJUSTMENTS
WHEEL ALIGNMENT
See WHEEL ALIGNMENT SPECIFICATIONS & PROCEDURES in WHEEL
ALIGNMENT section.
WHEEL BEARING
NOTE: Bearings should be cleaned, inspected, replaced (if
necessary) and lubricated before adjustment.
CAUTION: Never preload tapered roller bearings or damage to roller
ends will result. Bearings are designed to have a slightly
loose feel when properly adjusted.
2WD Models
1) Raise and support vehicle. Remove wheel and tire
assembly. Remove hub dust cap, cotter pin and nut retainer. Ensure
bearings are thoroughly packed with lithium grease.
2) Rotate hub and rotor assembly by hand, and tighten
retainer nut to 17-25 ft. lbs. (23-34 N.m) to seat bearings.
3) Loosen retainer nut 1/2 turn while rotating hub. Then
retighten nut to 19 INCH lbs. (2 N.m). Install nut retainer and new
cotter pin. Clean hub dust cap and coat inside with clean grease.
Reverse removal procedure for remaining components.
4WD Models (Grand Wagoneer)
1) On models equipped with locking hubs, remove locking
hubs. See appropriate LOCKING HUBS article. On models without locking
hubs, remove hub dust cap and drive gear snap ring. See Fig. 1.
2) Remove drive gear, pressure spring and spring cup. On
all models, remove outer lock nut and lock washer. Tighten inner lock
nut to 50 ft. lbs. (68 N.m) while rotating wheel.
3) Back off inner lock nut 45-65 degrees while rotating
wheel. Install washer and outer lock nut. Tighten outer lock nut to
50 ft. lbs. (68 N.m). Reverse removal procedure to complete
installation.
REMOVAL & INSTALLATION
3) Loosen bolt on throttle control link. Pull on link end to
eliminate lash. Tighten adjusting bolt. Press extend button on
Exerciser Box. When ISA retracts, release button and disconnect
Exerciser Box. Connect ISA wiring and remove spring from throttle
control lever. Install and reconnect any parts removed and/or
disconnected.
999 Transmission with 6-Cylinder Engines
1) Disconnect throttle control rod spring. Use spring to
hold adjusting link in forward position, against nylon washer. Block
choke open and release fast idle cam.
2) Raise vehicle. Loosen both retaining bolts on adjusting
link clamp. DO NOT remove spring clip or nylon washer. Use a spare
spring to hold transmission throttle lever against forward stop.
3) Push adjusting link to eliminate lash and pull clamp to
rear so that bolt in rod bottoms in rear of slot in rod. Tighten
forward clamp retaining bolt.
4) Pull throttle control rod to the rear so that bolt in
rod bottoms in front of slot and tighten rear retaining bolt. Remove
spare spring. Lower vehicle and reconnect throttle control rod spring.
AW-4 Transmission with All Engines
1) With ignition off, retract cable self-adjusting mechanism
fully. Press cable button down and push cable plunger inward.
2) Rotate throttle lever to wide open throttle position.
While holding throttle lever in position, allow cable plunger to
extend. When plunger is fully extended, release throttle lever. Cable
is now adjusted.
SHIFT LINKAGE
Cable Linkage
1) Place gearshift lever in "P" position and raise vehicle.
Using a small screwdriver, unlock shift control cable by releasing
U-shaped cable adjuster clamp. Remove cable from mounting bracket.
2) Move transmission shift lever rearward until fully
seated into "P" detent. Ensure that driveshaft cannot be rotated.
Snap control cable into cable mounting bracket and replace U-shaped
cable adjuster clamp.
3) Lower vehicle and verify engine starting. Engine should
start only with shifter in "P" or "N" position.
Rod Linkage
1) Loosen shift rod trunnion jam nuts at transmission lever.
Remove shift rod-to-bellcrank lock pin. Disengage trunnion and shift
rod. Place selector lever in "P" position and lock steering column.
Move transmission shift lever to full rear Park position.
2) Adjust shift rod trunnion to obtain free pin fit in
bellcrank arm. Tighten jam nuts. On vehicles with shift lever on
column, make sure linkage lash is eliminated by pulling down on shift
rod and pushing up on outer bellcrank when tightening jam nuts.
3) Check steering column lock for ease of operation. Ensure
engine starts in "N" or "P", only. If starter engages in any drive
gear, or does not work in "N" or "P", check for proper shift linkage
adjustment or faulty neutral safety switch.
NEUTRAL SAFETY SWITCH
1) Switch combines functions of neutral safety switch and
back-up light switch. With transmission linkage properly adjusted,
switch should allow starter operation in "P" and "N" only.
2) To test switch, remove wire connector and test for
continuity between center pin of switch and case. Continuity should
Worn or dirty needle valve Clean carburetor, see
and seat ENGINE PERFORMANCE
Float sticking Readjust or replace
float see the ENGINE
PERFORMANCE section
Incorrect choke adjustment Reset choke adjustment
see ENGINE PERFORMANCE
Defective coil Replace coil
Improper spark plug gap Regap spark plugs
Incorrect ignition timing Reset ignition timing
see ENGINE PERFORMANCE
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Detonation Over-advanced ignition Reset ignition timing
timing see ENGINE PERFORMANCE
Defective spark plugs Replace spark plugs
Fuel lines clogged Clean fuel lines
EGR system malfunction Check and repair EGR
system
PCV system malfunction Repair PCV system
Vacuum leaks Check and repair
vacuum system
Loose fan belts Tighten or replace
fan belts, see ENGINE
PERFORMANCE
Restricted airflow Remove restriction
Vacuum advance malfunction Check distributor
operation
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Dieseling Binding carburetor linkage Eliminate binding
Binding throttle linkage Eliminate blinding
Binding choke linkage or Eliminate binding
fast idle cam
Defective idle solenoid Replace idle solenoid
see ENGINE PERFORMANCE
Improper base idle speed Reset idle speed, see
see ENGINE PERFORMANCE
Incorrect ignition timing Reset ignition timing
see ENGINE PERFORMANCE
Incorrect idle mixture Reset idle mixture,
setting see ENGINE PERFORMANCE
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Faulty Incorrect ignition timing Reset ignition timing
Acceleration see ENGINE PERFORMANCE
setting, see ENGINE
PERFORMANCE
Vacuum leak Eliminate vacuum leak
EGR valve malfunction Replace EGR valve
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Poor Gasoline Cracked or broken vacuum Replace vacuum hoses
Mileage hoses
Vacuum leaks Repair vacuum leaks
Defective ignition wires Replace wires
Incorrect choke setting Readjust setting, see
ENGINE PERFORMANCE
Defective vacuum advance Replace vacuum advance
Defective spark plugs Replace spark plugs
Binding carburetor power Eliminate binding
piston
Dirt in carburetor jets Clean and/or replace
jets
Incorrect float adjustment Readjust float
setting, see FUEL
Defective power valve Replace power valve,
see ENGINE PERFORMANCE
Incorrect idle speed Readjust idle speed
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Engine Stalls Improper float level Readjust float level
Leaking needle valve and Replace needle valve
seat and seat
Vacuum leaks Eliminate vacuum
leaks
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VACUUM PUMP - DIESEL TROUBLE SHOOTING
NOTE: This is GENERAL information. This article is not intended
to be specific to any unique situation or individual vehicle
configuration. The purpose of this Trouble Shooting
information is to provide a list of common causes to
problem symptoms. For model-specific Trouble Shooting,
refer to SUBJECT, DIAGNOSTIC, or TESTING articles available
in the section(s) you are accessing.
NOTE: Diesel engines mechanical diagnosis is the same as gasoline
engines for items such as noisy valves, bearings, pistons,
etc. The following trouble shooting covers only items
pertaining to diesel engines.
VACUUM PUMP (DIESEL) TROUBLE SHOOTING CHART
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CONDITION POSSIBLE CAUSE CORRECTION \
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Column not correctly See STEERING COLUMNS
aligned article
Broken lower joint Replace joint
Horn contact ring not See STEERING COLUMN
article
Bearing not lubricated See STEERING COLUMN
article
Shaft snap ring not Reseat or replace snap
properly seated ring
Plastic spherical joint See STEERING COLUMN
not lubricated article
Shroud or housing loose Tighten holding screws
Lock plate retaining See STEERING COLUMN
ring not seated article
Loose sight shield Tighten holding screws
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High Steering Column assembly See STEERING COLUMN
Shaft Effort misaligned article
Improperly installed dust Adjust or replace
shield
Tight steering universal See STEERING COLUMN
joint article
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High Shift Column is out of See STEERING COLUMN
Effort alignment article
Improperly installed Adjust or replace
dust shield
Seals or bearings not See STEERING COLUMNS
lubricated article
Mounting bracket screws Replace with new
too long shorter screws
Burrs on shift tube Remove burrs or replace
tube
Lower bowl bearing See STEERING COLUMN
assembled wrong article
Shift tube bent or broken Replace as necessary
Improper adjustment of See STEERING COLUMN
shift levers article
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Improper Trans. Sheared shift tube joint Replace as necessary
Shifting
Sheared lower shaft lever Replace as necessary
Improper shift lever See STEERING COLUMN
adjustment article