torque JEEP CHEROKEE 1988 Service Repair Manual

Disconnect throttle valve linkage on A/T models.
3) Remove coolant temperature sensor wire. Disconnect
throttle cable at bellcrank. Remove intake manifold bolts. Remove
intake manifold.
4) If exhaust manifold requires removal, raise and support
vehicle. Disconnect exhaust pipe. Remove oxygen sensor wire and remove
sensor. Remove manifold-to-cylinder head bolts. Remove exhaust
manifold.
Installation
1) Ensure all gasket surfaces are clean. Install manifolds
and gasket on cylinder head. Start all bolts and finger tighten.
Tighten bolts in proper sequence. See Fig. 1. Tighten bolts to
specification. See TORQUE SPECIFICATIONS table.
2) Clean oxygen sensor threads. Apply anti-seize on oxygen
sensor threads prior to installation. Install sensor and tighten to
specification. Reverse removal procedures to complete installation.
Fill and purge cooling system. See COOLING SYSTEM AIR PURGE under
ENGINE COOLING.
Fig. 1: Manifold Bolt Tightening Sequence
CYLINDER HEAD
Removal
1) Disconnect negative battery cable. Drain cooling system.
Remove air cleaner. Remove intake and exhaust manifolds. See INTAKE &
EXHAUST MANIFOLDS.
2) Disconnect and mark all hoses and electrical connections
at cylinder head. Disconnect and mark spark plug wires. Remove spark
plugs. Remove valve cover bolts.

Fig. 9: Measuring Oil Pump Gear End Clearance
TORQUE SPECIFICATIONS
TORQUE SPECIFICATIONS TABLE








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Application Ft. Lbs. (N.m)
Camshaft Sprocket Bolt .......................... 80 (109)
Connecting Rod Cap Nut ........................... 33 (45)
Cylinder Head Bolt
No. 8 ........................................ 100 (136)
All Others ................................... 110 (149)
Drive Plate-to-Converter Bolt .................... 22 (30)
EGR Valve Pipe Nut ............................... 30 (41)
Exhaust Manifold Bolt ............................ 23 (31)
Fan Bolt ......................................... 18 (24)
Flywheel-to-Crankshaft Bolt .................. ( 1) 50 (68)
Intake Manifold Bolt ............................. 23 (31)
Main Bearing Cap Bolt

Step 1 ........................................ 40 (54)
Step 2 ........................................ 70 (95)
Step 3 ....................................... 80 (109)
Oil Pump Retaining Bolt
Short .......................................... 10 (14)
Long ........................................... 17 (23)
Oxygen Sensor .................................... 35 (47)
Pulley-to-Vibration Damper Bolt .................. 20 (27)
Rocker Arm Bolt .................................. 19 (26)
Throttle Body-to-Intake Bolt ..................... 16 (22)
Torque Converter Drive
Plate-to-Crankshaft Bolt .................... (1) 40 (54)
Vibration Damper Bolt ....................... ( 2) 80 (109)
Water Pump Bolt .................................. 13 (18)
INCH Lbs. (N.m)
Front Cover-to-Block
Bolt ............................................ 60 (7)
Stud .......................................... 192 (22)
Oil Pan Bolt
1/4" X 20 ....................................... 84 (9)
5/16" X 18 .................................... 132 (15)
Oil Pump Cover Bolt ............................... 70 (8)
Valve Cover Bolt .................................. 55 (5)
( 1) - Tighten to specification and an additional 60 degrees.
( 2) - With bolt cleaned and threads lubricated with oil.









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ENGINE SPECIFICATIONS
GENERAL ENGINE SPECIFICATIONS
GENERAL ENGINE SPECIFICATIONS TABLE








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Application In. (mm)
Displacement
Cu. In. ............................................ 150
Liters ............................................. 2.5
Fuel System .......................................... TBI
HP @ RPM ...................................... 117 @ 5000
Torque Ft. Lbs. @ RPM ......................... 135 @ 3500
Compression Ratio .................................. 9.2:1
Bore ......................................... 3.88 (98.5)
Stroke ....................................... 3.19 (81.0)









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VALVE SPECIFICATIONS
VALVE SPECIFICATIONS TABLE








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Application In. (mm)
Intake ( 1)
Head Diameter ................ 1.905-1.915 (48.38-48.60)
Face Angle ......................................... 44

Seat Angle ..................................... 44 30'
Seat Width ................... ( 2) .040-.060 (1.02-1.52)
Stem Diameter .................... .311-.312 (7.89-7.98)
Stem Clearance ..................... .001-.003 (.02-.08)
Valve Lift ................................ .424 (10.76)

from intake manifold. Disconnect fuel lines at fuel rail. Fuel lines
are removed by squeezing the 2 retaining tabs against the fuel line
and pulling the fuel line from the connector. Use caution as these
fuel lines are under pressure.
3) Loosen drive belt tensioner and remove drive belt. Remove
power steering pump and bracket from intake manifold. Remove fuel rail
retaining bolts. Remove fuel rail and injector assembly.
4) Remove intake manifold heat shield. Disconnect EGR tube
fittings. Disconnect exhaust pipe from manifold. Disconnect oxygen
sensor. Remove retaining bolts and remove manifolds.
Installation
1) Install new gasket. Install exhaust and intake manifolds
and loosely install bolts. Install EGR tube between manifolds. Tighten
manifold bolts in proper sequence see Fig. 1. Tighten to
specifications, see TORQUE SPECIFICATIONS TABLE in this article.
2) Tighten EGR tube bolts. Apply anti-seize to oxygen sensor
threads prior to installation. Reverse removal procedures for
remaining components. Tighten bolts to specification.
3) Install new "O" rings on fuel line connectors prior to
installation. Ensure "CLICK" sound is heard when installing fuel
lines. This indicates that fuel lines are properly seated.
Fig. 1: Manifold Tightening Sequence (4.0L)
Courtesy of Chrysler Motors.
INTAKE & EXHAUST MANIFOLD (4.2L)
Removal
1) Remove air cleaner. Disconnect fuel line at carburetor.
Mark and disconnect all vacuum hoses, ventilation hoses and electrical
connectors at intake manifold.
2) Disconnect throttle cable at bellcrank. On A/T models,
disconnect throttle valve rod. On all models, remove PCV hose from
manifold. Drain cooling system. Remove coolant hoses from intake

oil pump retaining bolts.
CAUTION: DO NOT move oil pick-up pipe in pump body. If oil pick-up
pipe is moved, pick-up pipe must be replaced to ensure an
airtight seal.
Disassembly & Inspection
1) Disassemble pump. See Fig. 8. Use feeler gauge and
straightedge to check gear end clearance. Place straightedge across
gears and pump body. Using feeler gauge, determine thickness feeler
gauge which fits snugly between straightedge and gears.
2) With gears installed in pump body, insert feeler gauge
between gear tooth and inner wall of pump body to check gear-to-body
clearance. Rotate gears and measure clearance at each gear tooth.
3) Compare measurements to specification. See OIL PUMP
SPECIFICATIONS table. Repair as necessary if not within
specifications. Check pressure regulator valve for wear or binding in
pump body. Replace components if wear or binding exists.
OIL PUMP SPECIFICATIONS TABLE









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Application In. (mm)
Gear End Clearance ........... .004-.008 (.10-.20)
Gear-to-Body Clearance ....... .002-.004 (.05-.10)









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CAUTION: If pressure regulator valve is replaced, ensure replacement
valve is the same diameter as that removed. Different
diameter valves may be used.
Reassembly & Installation
1) Reverse procedures for reassembly and installation. Apply
Permatex No. 2 to pick-up pipe prior to installation. Using Pipe
Installer (J-21882), install pick-up pipe. Ensure pick-up pipe support\
bracket is aligned with pump cover bolt.
2) Fill gear cavity with petroleum jelly prior to installing
cover. Apply Loctite on pump cover area. Install cover and bolts.
Tighten bolts to specification. Check pump gears for freedom of
rotation.
3) Install oil pump and new gasket. Tighten retaining bolts
to specification.
Fig. 8: Exploded View of Oil Pump Assembly
Courtesy of Chrysler Motors.
TORQUE SPECIFICATIONS TABLE

TORQUE SPECIFICATIONS TABLE








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Application Ft. Lbs. (N.m)
Camshaft Sprocket Bolt .......................... 80 (109)
Connecting Rod Cap Nut ........................... 33 (45)
Crankshaft Pulley-to-Damper Bolt ................. 20 (27)
Cylinder Head Bolt
4.0L
No. 11 .................................... 100 (135)
All Others ................................. 110 (149)
4.2L
No. 11 ..................................... 75 (102)
All Others .................................. 85 (115)
Exhaust Pipe-to-Manifold Bolt .................... 20 (27)
Fan & Hub Bolt ................................... 18 (24)
Flywheel-to-Crankshaft Bolt .................... 105 (142)
Fuel Rail Bolt ................................... 20 (27)
Intake & Exhaust Manifold Bolt
4.0L
Exhaust Manifold Bolts 1-5 ................... 23 (31)
Exhaust Manifold Bolts 6-7 .................. 17 (23)
Exhaust Manifold Bolts 8-11 ................. 23 (31)
Exhaust Manifold Bolts 12-13 ................ 30 (41)
4.2L ........................................... 23 (31)
Main Bearing Cap Bolt
Step 1 ......................................... 40 (54)
Step 2 ......................................... 70 (95)
Step 3 ........................................ 80 (109)
Oil Pump Attaching Bolt
Short .......................................... 10 (14)
Long ........................................... 17 (23)
Oxygen Sensor .................................... 35 (47)
Rocker Arm Bolt .................................. 19 (26)
Vibration Damper Bolt ....................... (1) 80 (109)
Water Pump Bolts ................................. 13 (18)
INCH Lbs. (N.m)
Engine Front Cover
Bolt ............................................ 60 (7)
Studs ......................................... 192 (22)
Oil Pan Bolt
1/4" X 20 ....................................... 84 (9)
5/16" X 18 .................................... 132 (15)
Oil Pump Cover Bolt ............................... 70 (8)
Valve Cover Bolt .................................. 55 (5)
( 1) - Clean and lubricate with oil prior to tightening.









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ENGINE SPECIFICATIONS
GENERAL ENGINE SPECIFICATIONS
GENERAL SPECIFICATIONS TABLE








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Application In. (mm)
4.0L
Displacement

Cu. In. .......................................... 242
Liters ........................................... 4.0
Fuel System ........................................ MPI
HP@RPM ...................................... 173 @ 2500
Torque Ft. Lbs.@RPM ......................... 220 @ 2500
Compression Ratio ................................ 9.2:1
Bore ....................................... 3.88 (98.4)
Stroke ..................................... 3.44 (87.4)
4.2L
Displacement
Cu. In. .......................................... 258
Liters ........................................... 4.2
Fuel System ..................................... 2-Bbl.
HP@RPM ...................................... 112 @ 3000
Torque Ft. Lbs.@RPM ......................... 210 @ 2000
Compression Ratio ................................ 9.2:1
Bore ....................................... 3.75 (95.3)
Stroke ..................................... 3.90 (98.9)









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VALVE SPECIFICATIONS
VALVES SPECIFICATIONS TABLE








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Application In. (mm)
4.0L
Intake
Head Diameter ........................... 1.91 (48.51)
Face Angle ....................................... 45

Seat Angle ..................................... 44.5
Seat Width ..................... .040-.060 (1.02-1.52)
Stem Diameter ............................ .312 (7.92)
Stem Clearance ................... .001-.003 (.03-.08)
Valve Lift .............................. .424 (10.76)
Exhaust
Head Diameter ........................... 1.50 (38.10)
Face Angle ....................................... 45

Seat Angle ..................................... 44.5
Seat Width ..................... .040-.060 (1.02-1.52)
Stem Diameter ............................ .312 (7.92)
Stem Clearance .................. .001-.003 (.03-.003)
Valve Lift .............................. .424 (10.76)
Valve Spring Height Installed ............ 1.625 (41.29)
4.2L
Intake
Head Diameter .................. 1.78-1.79 (45.3-45.5)
Face Angle ....................................... 29

Seat Angle ....................................... 30
Seat Width ..................... .040-.060 (1.02-1.52)
Stem Diameter ................ .3715-.3725 (9.44-9.46)
Stem Clearance ................... .001-.003 (.03-.08)
Valve Lift .............................. .405 (10.29)
Exhaust
Head Diameter .................. 1.40-1.41 (35.6-35.8)
Face Angle ....................................... 44

Seat Angle ..................................... 44.5
Seat Width ..................... .040-.060 (1.02-1.52)
Stem Diameter ................ .3715-.3725 (9.44-9.46)
Stem Clearance ................... .001-.003 (.03-.08)
Valve Lift .............................. .405 (10.29)
Valve Spring Height Installed ...................... ( 1)

TCC Torque Converter Clutch 

TCCS Toyota Computer Control System 

TDC Top Dead Center 

TDCL Total Diagnostic Communication Link 

TFI Thick Film Ignition system 

TGS Top Gear Switch (cancels SIL in top gear) 

THERMAC Thermostatic Air Cleaner 

THS Transmission Hydraulic Switch 

TP/TPS Throttle Position Sensor 

TPI Tuned Port Injection 

TPS Throttle Position Sensor/Switch 

TS Temperature Sensor 

TSB Technical Service Bulletin 

TTS Transmission Temperature Switch 

TV Thermovalve 

TWC Three-Way Catalyst 

Temp. Temperature 

Trans. Transaxle/Transmission 











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"V" ABBREVIATION TABLE
"V" ABBREVIATION TABLE







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ABBREVIATION DEFINITION 










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V Valve 

VAF Vane Air Flow sensor or circuit 

VAPS Variable Assist Power Steering 

VAT Vane Air Temperature 

VATS Vehicle Anti-Theft System 

VBATT Vehicle Battery Voltage 

VCC Viscous Converter Clutch 

VIN Vehicle Identification Number 

VIO Violet 

VLR Volt Loop Reserve 

VM Vacuum Modulator 

VM Vane Meter 

VOM Volt-Ohmmeter (Analog) 

VPWR Vehicle Power supply voltage (10-14 volts) 

VREF Voltage Reference (ECA supplied reference voltage 

VRV Vacuum Regulator Valve 

VSC Vehicle Speed Control sensor or signal 

VSS Vehicle Speed Sensor or signal 

VSV Vacuum Switching Valve 

Vac. Vacuum 

Volt. Voltage 











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"W" ABBREVIATION TABLE
"W" ABBREVIATION TABLE







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ABBREVIATION DEFINITION 










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W/ With 

W/O Without 

WAC WOT A/C Cut-off switch or circuit 

WAC Wide Open Throttle A/C Switch 

WHT White 

WOT Wide Open Throttle 

YEL Yellow 

\003
AU TO T R AN S D IA G NO SIS - A W 4

1988 J e ep C hero ke e
AUTOMATIC TRANSMISSIONS
Aisin Warner 4 Electronic Diagnosis
APPLICATION
NOTE: Transmission may also be referred to as AW-4.
TRANSMISSION APPLICATION









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Vehicle Application Transmission Model
Jeep
1987-96 Cherokee ................................... AW4
1987-92 Comanche ................................... AW4
1987 Grand Wagoneer ................................ AW4
1987-90 Wagoneer ................................... AW4
1992 Wrangler ...................................... AW4









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NOTE: Vehicle body code may be required when diagnosing or
repairing transmission, as body code may be used instead of
vehicle model name. See BODY CODE DESIGNATION table.
BODY CODE DESIGNATION









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Vehicle Model Body Code
Cherokee .............................................. XJ
Comanche .............................................. MJ
Grand Wagoneer ........................................ SJ
Wagoneer .............................................. XJ
Wrangler .............................................. YJ









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DESCRIPTION
The electronic control system for the AW-4 transmission
controls transmission shift points and torque converter lock-up.
Electronic control system consists of Transmission Control Module
(TCM), valve body solenoids, throttle position sensor, speed sensor,
neutral safety switch and brake switch.
NOTE: Transmission Control Module (TCM) may be referred to as
Transmission Control Unit (TCU). Neutral safety switch may
be referred to as park/neutral safety switch or gear select
switch.
OPERATION
TRANSMISSION CONTROL MODULE (TCM)
The TCM determines shift points and torque converter lock-up
based on input signals received from throttle position sensor, neutral
safety switch, speed sensor and brake switch. The TCM controls
transmission shift points and torque converter lock-up by operating
electric solenoids mounted on the valve body.
The TCM contains a self-diagnostic system used for
determining an electronic component failure. The TCM self-diagnostic

system will store a diagnostic trouble code in the TCM memory if
certain electronic problems exist. If electronic problem goes away,
diagnostic trouble code will be erased from TCM memory after ignition
has been cycled approximately 75 times.
NOTE: Diagnostic trouble code may be referred to as fault code.
Diagnostic trouble codes can be retrieved using a Diagnostic
Readout Box-II (DRB-II). After repairing an electrical system problem,\
stored diagnostic trouble code must be cleared from TCM memory.
The TCM is located behind right side of instrument panel on
Cherokee. See Fig. 1.
Fig. 1: Transmission Control Module (TCM) I.D. (Cherokee)
Courtesy of Chrysler Corp.
VALVE BODY SOLENOIDS
Valve body solenoids, mounted on the valve body, are output
devices controlled by signals received from the TCM. See Fig. 2. The
No. 1 and 2 valve body solenoids control transmission shifts while the
No. 3 valve body solenoid is used for torque converter lock-up.
When No. 1 and 2 valve body solenoids are energized,
solenoid plunger moves from seat. This opens the drain port and
releases line pressure. When either valve body solenoid is de-
energized, plunger closes the drain port.
The No. 3 valve body solenoid operates in reverse. When No. 3
valve body solenoid is de-energized, solenoid plunger moves away from
seat. This opens the drain port and releases line pressure. When No. 3
valve body solenoid is energized, the plunger closes the drain port.