🏷️ Basic Information

Make:

Hummer

Model:

H1

Year:

2004

Series:

Commercial H1

Chassis Codes:

HMCS, HMCO, XLC2, KSC4, KSCS, KSCO

👋 Introduction

Positioning:

Specialized off-road vehicle, known for its extreme capabilities and robust construction. The commercial variants often served specialized utility or military applications, demanding reliable and specific parts availability.

Vehicle Characteristics:

Unparalleled off-road prowess, robust chassis, high ground clearance, Central Tire Inflation System (CTIS) in some configurations, significant towing and payload capacity, powerful diesel engine.

📋 Manual Details

Systems Covered:

Engine, Fuel System, Emissions, Exhaust System, Cooling System, Transmission, Transfer Case, Wheels and Tires, Brake System, Steering System, Axles, Suspension, Frame, Body, Heating, Ventilation, Air Conditioning (HVAC), Electrical System, Accessories

Estimated Pages:

Extensive (typical for a comprehensive parts catalog, likely several hundred pages)

Type:

Parts Catalog

Catalog Purpose:

Illustrated Parts Catalog (IPC) - for identifying and ordering replacement parts.

Language:

English

Format:

PDF

📖 Manual Coverage

Detailed Systems:

Engine (6.5L Turbo Diesel), Fuel Delivery, Emission Controls, Exhaust Manifold and Piping, Radiator and Cooling Components, Transmission Operation, Transfer Case Mechanisms, Wheel Assemblies, Brake Calipers and Lines, Steering Linkages and Pumps, Front and Rear Axle Assemblies, Suspension Components (Springs, Shocks, Control Arms), Frame Construction, Body Panels and Trim, HVAC Ducts and Controls, Electrical Harnesses and Components, Accessory Mounting

Procedures:

Component Identification, Part Number Referencing, Exploded View Diagrams, Assembly Sequences for Parts, Interchangeability Information (potential), System Component Overviews

Depth:

High (focus on part identification and illustration for service and replacement; assumes a baseline understanding of vehicle systems for interpretation)

Diagnostic Scope:

Focuses on identifying and ordering correct replacement parts. Does not typically include diagnostic procedures or repair instructions, as this is a parts catalog, not a service manual.

📊 Manual Specifications

File Type:

Portable Document Format (PDF)

Operating Systems:

All Versions of Windows & Mac

Software Needed:

Adobe Acrobat Reader or compatible PDF viewer

Quality:

High Resolution for clear illustrations and text (dependent on original source quality)

Binding:

N/A (Digital PDF)

Paper:

N/A (Digital PDF)

⚙️ Engine Specifications

Engine Type:

V8 Turbocharged Diesel

Displacement:

6.5 Liters (395 cubic inches)

Bore X Stroke:

4.06 in x 3.82 in (103.2 mm x 97.0 mm)

Compression Ratio:

20.25:1

Horsepower:

Approx. 195-205 hp @ 3400 rpm (specific output may vary slightly by tune)

Torque:

Approx. 430-440 lb-ft @ 1600 rpm (specific output may vary slightly by tune)

Fuel Type:

Diesel Fuel

Injection System:

Direct Injection (Bosch VE or similar rotary pump)

Cooling Type:

Liquid-cooled, pressurized system with engine-driven fan or electric fan.

Emission Controls:

Catalytic converter (depending on market), EGR (Exhaust Gas Recirculation) potentially present.

Engine Designation:

6.5L GM V8 Turbo-Diesel (L400/L76 variants common)

🔧 Transmission

Transmission Type:

4-Speed Automatic Transmission (e.g., 4L80-E or similar heavy-duty unit)

Transmission Type:

5-Speed Manual Transmission (less common in commercial variants)

Transfer Case:

2-Speed Transfer Case with Lockable Center Differential (likely with CTIS integration for commercial models)

Automatic Transmission Fluid:

GM DEXRON-III (or equivalent)

Automatic Gear Ratios:

Specific ratios for 4L80-E: 2.48:1 (1st), 1.48:1 (2nd), 1.00:1 (3rd), 0.75:1 (4th), 2.08:1 (Reverse)

Transfer Case Ratios:

Low Range: 2.72:1, High Range: 1.00:1 (typical)

📐 Dimensions

Overall Length:

Varies significantly by body style (e.g., ~187 inches for some wagon models to over 200 inches for extended body variants)

Overall Width:

Approx. 86.5 inches (without mirrors)

Overall Height:

Varies by body style (e.g., ~75-80 inches)

Wheelbase:

Varies by body style (e.g., 130 inches for standard models)

Curb Weight:

Approx. 6,800 - 7,500 lbs (depending on configuration)

Gross Vehicle Weight Rating:

Up to 10,000 lbs or higher for specific commercial applications.

Cargo Volume:

Highly variable by body style, with truck bed variants offering significant utility.

Standard Tire Size:

37x12.50R17 (LT - Light Truck bias ply or radial, often run at lower pressures for off-road)

Wheel Bolt Pattern:

8x6.5 inches (8x165.1 mm)

Wheel Size:

17x8.5 inches

🛡️ Safety Features

Crash Test Ratings:

Not typically rated by NHTSA due to its specialized nature and limited production numbers in consumer markets. Focus is on inherent robustness.

Standard Safety:

Robust frame and body construction, three-point seat belts, reinforced roll cage (integral to body structure).

Braking System:

Four-wheel disc brakes, power-assisted with anti-lock braking system (ABS).

Traction Control:

Available on some models, leveraging ABS and drivetrain components.

💡 Technology Features

Audio System:

Basic AM/FM stereo with CD player or cassette player, depending on trim and options. Likely aftermarket upgrades common.

ABS:

Standard Anti-lock Braking System (ABS).

Vehicle Systems:

Focus on mechanical and electrical integrity for extreme environments rather than advanced digital connectivity. CTIS system is a key technological feature for tire management.

🔧 Maintenance

Oil Change Interval:

Typically every 3,000-5,000 miles or 6 months, whichever comes first, for diesel engines. Consult the manual for exact intervals.

Transmission Fluid Change:

Every 30,000-60,000 miles or as specified in the manual, particularly for heavy-duty use.

Engine Oil Type:

Diesel Engine Oil, API CH-4 or CI-4 rated (e.g., 15W-40 or 5W-40 synthetic for colder climates).

Engine Oil Capacity:

Approx. 9.5 quarts (9 liters) with filter.

Coolant Type:

Ethylene Glycol based coolant, typically a green or orange type (Dex-Cool compatible or similar).

Coolant Capacity:

Approx. 17-19 quarts (16-18 liters).

Brake Fluid Type:

DOT 3 or DOT 4 (ensure compatibility with ABS)

Power Steering Fluid:

GM Power Steering Fluid or Dexron-III (check manual)

Gear Oil Type:

API GL-5, 75W-90 or 80W-90 for differentials and transfer case.

Common Wear Items:

CV joints, brake components, suspension bushings, hub seals, radiator hoses, glow plugs, alternator, starter.

Diesel Specific:

Injector pump seals, turbocharger wear, potential for head gasket issues if overheated, intake manifold clogging due to EGR.

📚 Vehicle History

Origin:

Developed from the AM General High Mobility Multipurpose Wheeled Vehicle (HMMWV/Humvee). Hummer brand was established for civilian versions.

Development:

Civilian adaptation of the military Humvee. The H1 design remained largely consistent throughout its production life, with gradual improvements and engine updates.

Production Period:

Civilian H1 production ran from 1992 to 2006. 2004 is within this primary production window.

Manufacturing Location:

AM General's assembly plant in Mishawaka, Indiana, USA.

🏆 Awards & Recognition

Industry Acclaim:

While not typically winning consumer awards in the traditional sense, the H1 is widely recognized for its unmatched off-road capability and military lineage.