Gear JEEP CHEROKEE 1988 Service Service Manual

CO M PU TE R R ELE A R N P R O CED URES

1988 J e ep C hero ke e
GENERAL INFORMATION
Computer Relearn Procedures
All Models
* PLEASE READ THIS FIRST *
The following general procedures are to be used if
driveability problems are encountered after power loss or battery has
been disconnected. These procedures may provide an aid in eliminating
these problems.
To reduce the possibility of complaints, after any service
which requires battery power to be disconnected, vehicle should be
road tested.
COMPUTER RELEARN PROCEDURES
Vehicles equipped with engine or transmission computers may
require a relearn procedure after vehicle battery is disconnected.
Many vehicle computers memorize and store vehicle operation patterns
for optimum driveability and performance. When vehicle battery is
disconnected, this memory is lost. The computer will use default data
until new data from each key start is stored. As computer memorizes
vehicle operation for each new key start, driveability is restored.
Vehicle computers may memorize vehicles operation patterns for 40 of
more key starts.
Customers often complain of driveability problems during
relearn stage because vehicle acts differently then before being
serviced. Depending on type and make of vehicle and how it is
equipped, the following complaints (driveability problems) may exist:
* Harsh Or Poor Shift Quality
* Rough Or Unstable Idle
* Hesitation Or Stumble
* Rich Or Lean Running
* Poor Fuel Mileage
These symptoms and complaints should disappear after a number
of drive cycles have been memorized. To reduce the possibility of
complaints, after any service which requires battery power to be
disconnected, vehicle should be road tested. If a specific relearn
procedure is not available, the following procedure may be used:
Automatic Transmission
* Set parking brake, start engine in "P" or "N" position.
Warm-up vehicle to normal operating temperature or until
cooling fan cycles.
* Allow vehicle to idle for one minute in "N" position. Select
"D" and allow engine to idle for one minute.
* Accelerate at normal throttle position (20-50%) until vehicle
shifts into top gear.
* Cruise at light to medium throttle.
* Decelerate to a stop, allowing vehicle to downshift, and use
brakes normally.
* Process may be repeated as necessary.
Manual Transmission

Fig. 2: Exploded View of Split Case (4-Pinion)
2) Drive vehicle over formica board until one rear wheel is
in the center of board and paper. Place a block of wood 2" high and a
minimum of 3" wide in front of one of the front wheels.
3) Open throttle gradually attempting to slowly drive vehicle
over block of wood. If paper slips out of position, reposition paper
and repeat test. If vehicle drives over block of wood, axle is
functioning properly.
DANA 4-PINION POWER-LOK
1) With engine off and transmission in "N", raise one wheel
off ground. Block both front and rear wheels of opposite side. Install
adapter tool across 2 wheel studs and attach torque wrench to center
of tool.
2) Observe torque required to continuously turn wheel
smoothly through several revolutions. Repeat test for opposite side.
If differential is okay, torque should be 40-200 ft. lbs. (54-272 N.
m). Disregard breakaway torque. Use rotating torque only.
NOTE: Exploded view of Chrysler Motors Trac-Lok differential was
not available from manufacturer.
REMOVAL & INSTALLATION
See DANA SEMI-FLOATING or FULL-FLOATING AXLE article in this
section.
OVERHAUL
DANA 2-PINION TRAC-LOK
NOTE: For front axle shaft and bearing removal, see articles on
DANA FULL-FLOATING AXLES or 4WD STEERING KNUCKLES in this
section. With the exception of ring gear and differential
side bearings, Chrysler Motors does not recommend disassembly
of differential. If repair is required, manufacturer
recommends replacing entire unit as an assembly.
Disassembly (Jeep)
1) Using 2 screwdrivers, remove pinion snap rings. Using a
brass drift and a hammer, remove pinion shaft from case. Install Step

Plate (J 23781-7) in bottom side gear. Install grease in centering
hole of step plate. Position Rotating Tool (J 23781-3) on step plate
tool. Coat threads of Forcing Screw (J 8646-2) with oil.
2) Insert forcing Screw (J 8646-2) through case and thread
into rotating tool. Thread screw through tool until it contacts
centering hole in step plate. Tighten forcing screw to relieve clutch
pack tension from pinions. Remove pinion thrust washers.
3) Tighten forcing screw until all clutch pack tension is
relieved from pinions. Slide rotating tool pawl so it engages with
side gear teeth. Rotate side gears with rotating tool until pinions
can be removed through case opening.
4) Remove forcing screw, rotating tool, upper side gear and
clutch pack. Remove differential case from axle shaft. Remove
remaining side gear, clutch pack and step plate tool. Remove retainer
clips from clutch packs. Mark clutch packs for reassembly reference.
Using a press, remove differential bearings.
Cleaning & Inspection
Clean all parts and dry with compressed air. If any clutch
plates or discs require replacement, all plates and discs should be
replaced. Replace any worn or damaged components.
NOTE: For adjustment procedures, see DANA SEMI-FLOATING or
FULL FLOATING AXLE articles in this section
Reassembly
1) Lightly lubricate clutch pack discs with axle lubricant.
Assemble clutch pack discs and install retaining clips on ears of
discs. See Fig. 3. Install assembled clutch packs on side gears.
Fig. 3: Typical Clutch Pack Assembly
2) Mount differential case on axle shaft. Install first
clutch pack and side gear in bottom bore of case. Ensure retaining
clips remain seated in case pockets. Install Step Plate (J 8646-2) in

clutch pack just installed.
3) Install remaining side gear and clutch pack in case. Hold
assembly in position and install rotating tool and forcing screw.
Tighten forcing screw and compress clutch packs. Install pinions.
Rotate side gear with tool pawl until each pinion is aligned with
pinion shaft bore.
4) Install pinion thrust washers and pinion shaft. Install
pinion thrust washers and pinion shaft. Install snap rings on pinion
shaft. Remove differential from axle shaft. Remove shaft from vise.
Using Remover (J 22912-01), remove differential bearings. Install end
play shims on each side of case. Reinstall differential bearings.
5) Position ring gear on differential case. Install NEW ring
gear bolts and tighten to 52 ft. lbs. (70 N.m).
DANA 4-PINION POWER-LOK
NOTE: Differential bearings do not need to be removed to overhaul.
Disassembly
1) Mark case halves, pinion mate shafts and ramps for
reassembly reference. Clamp differential assembly in soft-jawed vise
and loosen case half bolts ( DO NOT remove bolts). Position
differential assembly on bench with ring half of case down. Remove
case attaching bolts. Remove cover half of case.
2) Remove pinion mate gear, side gear ring and clutch pack.
Keep parts together for reassembly reference. Remove parts from drive
gear half of case.
Cleaning & Inspection
Clean all parts and dry with compressed air. If any clutch
plates or discs require replacement, it is recommended that all plates
and discs be replaced. Replace any part that is worn or damaged.
Reassembly
NOTE: For adjustment procedures, see DANA SEMI-FLOATING or
FULL FLOATING AXLE articles in this section.
1) Position side gear ring from drive gear half of case on a
pinion flange. Coat clutch plates with Hypoid Gear Lubricant (C6A-Z-
19580-E). Reassemble parts in correct order. See Fig. 1. Install ring
gear half of case over clutch pack and side gear ring. Ensure clutch
plate lugs enter slots in case and case bottoms on clutch pack.
2) Hold assembly together and turn case half upside down.
Install gear in side gear ring. Install mate shaft and pinions on side
gear ring. Align mate shaft and case markings. Install cover half mate
shaft and pinions. Align markings.
3) Install side gear on pinions. Position side gear ring on
side gear and pinions. Assemble clutch pack on side gear. See Fig. 4.
Align clutch plate lugs and install all parts in case. Position cover
half of case over assembly. Align case marks made during disassembly.
4) Lubricate bolt threads with axle lube and install case
bolts. Using both axle shafts, align splines of side gear and side
gear ring. Tighten case bolts to 65-70 ft. lbs. (89-94 N.m).
5) Remove axle shafts. If properly assembled, each pinion
mate cross shaft should be tight on its ramp. If clearance is present,
it should not exceed .010" (.254 mm).

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DRIV E A XLE - F U LL F LO ATIN G

1988 J e ep C hero ke e
Drive Axles - Dana Full-Floating Axles
Jeep Front & Rear Drive Axles
DESCRIPTION
The axle assembly is an integral carrier type with hypoid
gear ring and pinion. Stamped steel cover is removable for inspection
and repair of differential. Vehicle loads are carried by axle
housings. Axle shafts of "full-floating" rear assemblies may be
removed without disturbing wheel bearings.
Drive pinion depth, pinion bearing preload and differential
side bearing preload are all set by shims.
See LOCKING HUB and 4WD STEERING KNUCKLE articles in this
section for removal and installation procedures for these front drive
axle component parts.
AXLE RATIO & IDENTIFICATION
A metal tag on axle is stamped with gear ratio, part numbers
and limited slip identification. To determine drive axle ratio, refer
to MODEL IDENTIFICATION BY RING GEAR SIZE table.
MODEL IDENTIFICATION BY RING GEAR SIZE









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Model Ring Gear Diameter
44 ....................................... 8.50"
60 ....................................... 9.75"
61 ....................................... 9.75"
70 ...................................... 10.50"
80 ...................................... 11.25"









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FRONT HUB, BEARING, SPINDLE & AXLE SHAFT R & I
FRONT HUB BEARING ADJUSTING SPECIFICATIONS








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Application ( 1) Ft. Lbs. (N.m)
Adjusting Nut
Step 1 ............................... 50 (68)
Step 2 .......................... Back Off 20

Lock Nut ............................... 50 (68)
( 1) - While Rotating Hub.









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REMOVAL (CHEROKEE, COMANCHE & WAGONEER)
1) Raise and support vehicle. Remove tire and wheel assembly.
Remove disc brake caliper and support out of way.
2) Match mark disc rotor and hub and remove disc rotor.
Remove cotter pin, nut lock and axle hub nut. Remove hub-to-knuckle
bolts. Pull hub assembly off axle shaft. Pull axle shaft through
knuckle to remove. Inspect axle shaft "U" joint and shaft splines for
wear. Replace as necessary.
3) Press hub out of bearings. Remove seals and bearings.

Inspect bearings and races for wear and pitting. Replace bearing and
race together.
INSTALLATION
1) Install axle shaft through knuckle and engage in axle gear
splines. Pack bearings with multi-purpose grease and fill cavities in
bearing hub. Install new seals.
2) Press hub into bearings. Install hub assembly on axle
shaft and install bolts. To complete installation, reverse removal
procedure. See TORQUE SPECIFICATIONS table at end of this article.
INTERMEDIATE AXLE SHAFT R & I
REMOVAL (DISCONNECT AXLE MODELS)
1) Remove outer axle. See FRONT HUB, BEARING, SPINDLE & AXLE
SHAFT in this article.
2) Remove axle assembly inspection cover and drain fluid.
Remove vacuum and electrical connections at disconnect housing
assembly. Remove bolts and pull disconnect housing from axle tube. See
Fig. 1 .
3) Remove intermediate shaft retaining clip on inner end of
axle shaft. Carefully slide intermediate axle shaft through seal and
out end of axle tube. Remove shift collar.
4) Inspect intermediate shaft bearings and seals for wear. If
replacement of bearings or seal is necessary, use recommended tools.
5) On Jeep, use Tool Set (J-34659), Slide Adapter (J-34659-\
4)
and Over Rod (J-34659-3) to replace intermediate shaft bearings and
seal.
Fig. 1: View Of Axle Disconnect Assembly
Courtesy of Chrysler Motors.
INSTALLATION

1) Coat intermediate shaft with lubricant and carefully slide
through seal and engage in drive axle splines. Install retaining clip.
2) Install shift collar on axle shaft. Install outer axle
shaft and check for smooth operation of shift collar.
3) Apply bead of silicone sealer to inspection cover and
install cover. Fill axle housing with 2.5 pts. (1.2L) of 75W 90 gear
oil. Pour a small amount of gear oil on shift collar and install
disconnect housing. Ensure shifting fork is properly positioned in
shift collar.
4) To complete installation, reverse removal procedure.
Tighten all bolts and nuts to specification. See TORQUE SPECIFICATIONS
table at end of this article.
FRONT AXLE ASSEMBLY R & I
REMOVAL (CHEROKEE, COMANCHE, WAGONEER)
1) Raise and support vehicle. Remove tire and wheel assembly.
Remove hubs, spindles and axles. See FRONT HUB, BEARING, SPINDLE &
AXLE SHAFT in this article.
2) Disconnect vacuum hoses and electrical connections from
shift motor. Disconnect stabilizer bar, track bar and steering damper.
3) Disconnect drive shaft at pinion yoke and tie to frame.
Remove left and right tie rod ends from knuckles.
4) Support axle assembly on floor jack. Remove lower shock
mounts. Disconnect axle housing-to-frame control arms at axle. Lower
floor jack slowly and remove axle assembly. Remove coil spring lower
bracket and coil spring.
INSTALLATION
1) Place axle housing on floor jack and position under
vehicle. Install coil springs and raise assembly into position. Ensure
top of coil springs seat in spring pocket.
2) Check all bushings and mounting hardware for wear or
damage. To complete installation, reverse removal procedure. Tighten
all bolts and nuts to specification. See TORQUE SPECIFICATIONS table
at end of this article. Fill axle assembly with gear oil. Check wheel
alignment.
REAR HUB, BEARINGS & AXLE SHAFTS R & I
1) Raise and support vehicle. Remove tire and wheel assembly.
Remove axle flange nuts or bolts. If nuts are used, rap center of axle
flange sharply with hammer to loosen tapered dowels. Remove bolts or
dowels and pull axle shaft out of hub.
2) Depending on application, bend back ears of lock washer,
or remove locking wedge from nut, or remove snap ring and key. Remove
bearing adjusting nut(s) and remove hub assembly.
3) Remove inner hub seal and bearing. Inspect bearings and
races for wear. To replace bearing, drive outer race from bearing hub
using a punch and hammer. Install new race being careful not to chip
or dent race. Ensure new race is seated in hub.
4) Pack bearings with multi-purpose grease. Install new seal.
Carefully install hub on axle spindle to avoid damaging seal lip and
spindle threads.
5) Install outer bearing and adjusting nut. Tighten bearing
adjusting nut in steps. See REAR HUB BEARING ADJUSTING SPECIFICATIONS
table. Install lock ring if used. Install spindle lock nut if used and
tighten to proper specification. See REAR HUB BEARING ADJUSTING
SPECIFICATIONS table.

Fig. 5: Removing Pinion Seal
INSTALLATION
Using Seal Installer (J22661), drive new seal into front
differential housing. See Fig. 6. Tighten yoke attaching nut to 210
ft. lbs. (285 N.m). Using NEW strap bolts, align and install drive
shaft. Tighten strap bolts to 14 ft. lbs. (19 N.m). Fill differential
with SAE 75W-90 gear lubricant.

Fig. 8: Exploded View Of Dana Full-Floating Axle Assembly
AXLE ASSEMBLY OVERHAUL
DISASSEMBLY
1) Drain lubricant. Remove axle shafts and housing cover. If
no side play is found in the differential case assembly, mount dial
indicator on pilot stud with tip against back of ring gear. Measure
runout of ring gear, marking ring gear and case at point of maximum
runout.
2) If runout total exceeds .006" (.15 mm), ring gear could b\
e
loose or case could be damaged. Using .003" (.08 mm) feeler gauge, try\
to force feeler gauge between cap and race. If it does, bearing race
may have been turning in carrier.
3) If race has been turning, carrier could be damaged.
Observe identifying letters stamped into bearing caps and face of
carrier sealing surface. Use these matched letters for reassembly
reference.
4) Remove side bearing caps. Use Housing Spreader (W-129-A on\

Model 44; D-167 on Models 60, 61, 70 and 80) to spread differential
housing to .015" (.38 mm). See Fig. 9.
CAUTION: DO NOT spread housing more than .020" (.51 mm). Permanent
damage to housing could result.
Fig. 9: Correct Procedure for Spreading Housing
5) Pry differential case out of housing. Remove spreader to
prevent carrier taking set. On models with side bearing shims between
carrier and side bearing outer race, record sizes and positions of
shims. Be careful not to damage machined surfaces of housing.
6) Put case in soft-jawed vise and remove ring gear bolts and