Segment:
Compact/Mid-size SUV (Off-Road Focused)
Key Competitors 2003:
Toyota 4Runner, Nissan Xterra, Land Rover Discovery, Ford Explorer
Vehicle Identity:
Iconic off-road capability, robust construction, removable doors and top, solid front axle (on most models).
Target Audience:
Jeep Wrangler TJ owners performing maintenance, repairs, modifications, or seeking in-depth technical understanding. Also valuable for professional mechanics.
Systems Covered:
Engine (including repair, timing, lubrication), Fuel and Emissions, Cooling and Heating, Transaxle (manual and automatic), Clutch, Differential, Driveshaft, Steering, Suspension, Brakes (including ABS), Body, Heater and Air Conditioning, Automatic Climate Control, Electrical, Supplemental Restraint System (SRS), Engine Repair, Air Conditioning, Exhaust Emissions Control, Ignition, Wiring Diagrams
Estimated Page Count:
Approximately 1500-2000 pages (typical for a comprehensive factory service manual)
Manual Type:
Factory Service Manual / Workshop Manual
Engine Systems:
Engine Removal/Installation, Cylinder Head/Valve Train, Engine Block, Engine Lubrication, Intake Manifold/Exhaust System, Cooling and Heating, Fuel and Emissions, Ignition, Valve Timing Procedures, Chain & Gear Replacement, Tensioner Adjustments, Tensioner Release & Reset Methods, Chain Routing & Sprocket/Gear, Valve Timing Marks
Routine Maintenance:
Tune-up Procedures, Fluid Checks and Changes, Filter Replacements, Belt Inspection and Replacement, Spark Plug Service
Repair And Rebuild:
Comprehensive Engine Repair, Cylinder Head Overhaul, Engine Block Machining, Transmission Rebuild (Manual & Automatic), Differential Service, Brake System Overhaul, Steering System Repair, Suspension Component Replacement, HVAC System Repair, Electrical System Diagnosis and Repair
Diagnostics:
Troubleshooting Guides, Diagnostic Trouble Codes (DTCs), Electrical Schematics, System Testing Procedures
Installation:
Component Removal & Installation, Body Panel Replacement, Accessory Installation
Depth Of Information:
In-depth coverage from basic maintenance and tune-ups to complete engine, transmission, and driveline rebuilds, including detailed diagnostic procedures, electrical schematics, and specifications. Suitable for professional technicians and experienced DIY enthusiasts.
Engine 1 Code:
4.0L Inline-6 (e.g., ERH)
Engine 1 Displacement:
3952 cc (241 cu in)
Engine 1 Configuration:
Inline 6-Cylinder, Overhead Valve (OHV)
Engine 1 Horsepower:
190 hp @ 4600 rpm (approx.)
Engine 1 Torque:
235 lb-ft @ 3200 rpm (approx.)
Engine 1 Fuel System:
Electronic Multi-Point Fuel Injection (MPI)
Engine 1 Bore X Stroke:
98.5 mm x 86.7 mm (3.88 in x 3.41 in) (approx.)
Engine 1 Compression Ratio:
8.75:1 (approx.)
Engine 2 Code:
2.4L 4-Cylinder (e.g., EDZ)
Engine 2 Displacement:
2429 cc (148 cu in)
Engine 2 Configuration:
Inline 4-Cylinder, Single Overhead Cam (SOHC)
Engine 2 Horsepower:
150 hp @ 5200 rpm (approx.)
Engine 2 Torque:
170 lb-ft @ 4000 rpm (approx.)
Engine 2 Fuel System:
Electronic Multi-Point Fuel Injection (MPI)
Engine 2 Bore X Stroke:
87.5 mm x 100.0 mm (3.44 in x 3.94 in) (approx.)
Engine 2 Compression Ratio:
9.1:1 (approx.)
Transmission Standard Engine 4.0L:
NV3550 5-Speed Manual Transmission
Transmission Standard Engine 2.4L:
AX-5 5-Speed Manual Transmission
Transmission Optional Engine 4.0L:
42RLE 4-Speed Automatic Transmission
Transmission Optional Engine 2.4L:
30RH 3-Speed Automatic Transmission
Transfer Case:
NP231 Command-Trac (standard) or optional NP241OR Rock-Trac (Rubicon models)
Gear Ratios Nv3550:
1st: 3.75, 2nd: 2.14, 3rd: 1.34, 4th: 1.00, 5th: 0.76, Reverse: 3.75 (approx.)
Gear Ratios 42Rle:
1st: 2.804, 2nd: 1.532, 3rd: 1.000, 4th: 0.715, Reverse: 2.142 (approx.)
Manual Transmission Fluid:
GL-3 or GL-4 75W-90 (e.g., Mopar Manual Transmission Lubricant)
Automatic Transmission Fluid:
ATF+4 (MS-9602) (e.g., Mopar ATF+4)
Transfer Case Fluid:
Mopar NV231/NV241 Transfer Case Lubricant or equivalent (e.g., SAE 75W-90 GL-4)
Wheelbase 2Door:
93.4 inches (2372 mm)
Wheelbase 4Door Unlimited:
103.4 inches (2626 mm)
Length 2Door:
160.5 inches (4077 mm)
Length 4Door Unlimited:
170.2 inches (4323 mm)
Width Body:
66.5 inches (1689 mm)
Height To Top Of Hardtop:
71.5 inches (1816 mm)
Curb Weight 2Door Approx:
3325 - 3575 lbs (1508 - 1622 kg)
Curb Weight 4Door Unlimited Approx:
3720 - 4025 lbs (1687 - 1826 kg)
Towing Capacity Max:
2000 lbs (907 kg) (2-door), 3500 lbs (1588 kg) (4-door Unlimited)
Gvw 2Door Max:
4700 lbs (2132 kg)
Gvw 4Door Unlimited Max:
5300 lbs (2404 kg)
NHTSA Rollover Resistance:
5 Star (for 2003 models)
ABS:
Available (Standard on some trims, optional on others)
Airbags:
Driver and Passenger Frontal Airbags (Standard)
Seatbelts:
3-point front seat belts with pretensioners, 3-point rear seat belts
Body Structure:
Body-on-frame construction with robust chassis
Oil Change Interval:
Every 3,000 miles or 3 months (severe duty) / Every 6,000 miles or 6 months (normal duty) - Refer to manual for exact schedule.
Tire Rotation Interval:
Every 6,000 miles
Spark Plug Replacement 4.0L:
Approx. 100,000 miles (Champion Copper Plus or equivalent recommended)
Coolant Flush Interval:
Every 5 years or 100,000 miles (using appropriate OAT coolant)
Engine Oil Type 4.0L:
API Certified SAE 10W-30 (or 5W-30 for extreme cold) - Synthetic recommended for better longevity.
Engine Oil Capacity 4.0L:
6 US quarts (5.7 Liters) with filter
Engine Oil Type 2.4L:
API Certified SAE 5W-30
Engine Oil Capacity 2.4L:
5 US quarts (4.7 Liters) with filter
Power Steering Fluid Type:
ATF+3 or ATF+4 (Refer to manual for precise specification)
Common Issues 4.0L:
Cracking exhaust manifolds, oil filter housing leaks, radiator leaks, occasional rear main seal leaks, water pump failures.
Common Issues 2.4L:
Head gasket issues, timing chain stretch, oil consumption.
Common Issues Drivetrain:
Dana 30/35 axle seal leaks, NP231 transfer case chain stretch, clutch wear (manual transmissions).
Common Issues Suspension Steering:
Worn ball joints, track bar bushings, steering stabilizer.
Jeep Legacy:
Roots in military vehicles, known for unparalleled off-road prowess and ruggedness since WWII.
Tj Generation Start:
1997
Updates For 2003:
Introduction of the Unlimited (LJ) platform, minor interior comfort updates, potential minor powertrain refinements. The 4.0L inline-6 was the dominant engine, renowned for its durability and torque.
Manufacturing Location:
Toledo, Ohio, USA
