🏷️ Basic Information Identification Make: GMC Model: K3500 Year: 1991 Codes Platform: GMT400 👋 Introduction Market Position Target Audience: DIY enthusiasts, independent repair shops, owners seeking detailed repair information. Competitive Analysis Comparison To Print: Offers superior convenience, searchability, and cost-effectiveness compared to traditional printed manuals. Instant access and always up-to-date (within the licensed year). Key Features Licensing: Officially licensed, derived from OE (Original Equipment) materials, ensuring accuracy and authenticity. Accessibility: Accessible on any PC, laptop, smartphone, or tablet with an internet connection. Value Proposition: Saves money on repair costs by empowering owners to perform maintenance and repairs themselves. Provides factory-level diagnostic and repair guidance. 📋 Manual Details Coverage Areas Primary Coverage: Service and Repair Additional Coverage: Diagnostics, Troubleshooting, Maintenance Page Count Estimated Page Count: Extensive (digital format with searchable content) Manual Type Type: Official Service and Repair Manual Software Language Language: English Format Format: Online Software Access (Web Browser Compatible) 📖 Manual Coverage Systems Covered Powertrain: Engine (mechanical and electrical), Fuel System, Exhaust System, Drivetrain (transfer case, driveshafts, axles) Chassis: Suspension (front and rear), Steering System, Brakes (front and rear, hydraulic and parking brake), Wheels and Tires Electrical: Wiring Diagrams, Lighting, Instrumentation, Power Distribution, Starting and Charging System, Audio System, Comfort and Convenience Systems Body: Body Structure, Doors, Hood, Tailgate, Glass, Interior Trim, Exterior Trim, Bumpers HVAC: Heating, Ventilation, and Air Conditioning (HVAC) System Procedures Included Maintenance: Oil changes, Filter replacements, Fluid checks and top-offs, Spark plug replacement, Belt inspection and replacement, Tune-up procedures Repair: Engine component replacement (e.g., alternator, water pump, starter), Brake system repair (e.g., caliper replacement, brake line repair), Suspension component replacement (e.g., ball joints, shock absorbers), Steering component replacement (e.g., tie rods, steering gearbox), Drivetrain component repair, Electrical component diagnosis and replacement Diagnostics: Troubleshooting guides for common symptoms, Diagnostic procedures for engine and electrical systems, Use of diagnostic tools (if applicable to the era) Technical Depth Depth: Comprehensive, covering everything from basic maintenance to major component overhauls and detailed electrical diagnostics. 📊 Manual Specifications File Format Access Method: Web-based access via internet connection and web browser. Print Quality Print Capability: Printable pages for specific sections or procedures. Binding Type Binding: N/A (Digital Format) Paper Type Paper Type: N/A (Digital Format) ⚙️ Engine Specifications Primary Engine Engine Options: Available with several robust engine options, including the 5.7L (350 ci) V8 and the 7.4L (454 ci) V8. A 4.3L (262 ci) V6 was also common in the K-series lineup, though less frequent in the K3500 which often favored heavier duty engines. Performance 5.7L V8 Horsepower: Approximately 210-230 hp (varies by specific tune and emissions controls). 5.7L V8 Torque: Approximately 300-320 lb-ft (varies by specific tune and emissions controls). 7.4L V8 Horsepower: Approximately 230 hp. 7.4L V8 Torque: Approximately 380-400 lb-ft. Fuel System Fuel Delivery: Throttle Body Injection (TBI) or Multi-Port Fuel Injection (MPFI) depending on the specific engine and trim. 🔧 Transmission Standard Standard Transmission: Typically mated to heavy-duty automatic transmissions like the 4L80-E (4-speed overdrive automatic) or the older TH400 (3-speed automatic) for the most powerful engines. Manual transmissions, such as the SM465 (4-speed manual with granny gear), were also available, particularly for heavy-duty applications. Optional Optional Transmission: If an automatic was standard, a manual might be optional, and vice-versa, depending on the specific configuration. Features Transfer Case: Often equipped with a robust 4WD transfer case (e.g., NP208 or NP241) for serious off-road and towing capability. 📐 Dimensions Exterior Body Styles: Regular Cab, Extended Cab (Crew Cab less common). Bed Lengths: Available in 8-foot (long bed) configurations. Short bed (6.5-foot) less common on K3500. Weights Gvwr: Gross Vehicle Weight Rating (GVWR) would be significantly higher than lighter duty K1500/K2500 models, typically exceeding 10,000 lbs for heavy-duty configurations. 🛡️ Safety Features Ratings Crash Testing: NHTSA ratings for this era are generally less comprehensive than modern standards. Emphasis on structural integrity for heavy-duty use. Active Features Braking System: Four-wheel disc brakes or front disc/rear drum brakes depending on configuration. Anti-lock braking system (ABS) may be available on rear wheels or all four wheels. Passive Features Restraints: Seat belts (lap and shoulder belts for front occupants). 💡 Technology Features Infotainment Audio System: Basic AM/FM stereo with cassette player. Optional premium sound systems or CD players may have been available on higher trims. Driver Assistance Cruise Control: Available as an option on most trims. Connectivity OBD I: Utilizes the OBD-I (On-Board Diagnostics, First Generation) system for engine diagnostics. The manual will detail diagnostic codes and procedures for this system. 🔧 Maintenance Service Intervals Oil Change Interval: Typically every 3,000-5,000 miles or 3-6 months, depending on driving conditions and oil type used. Consult the manual for specific recommendations. Transmission Fluid Change: Recommended every 30,000-60,000 miles, with filter changes. Specific interval depends on transmission type and usage (e.g., towing). Fluid Specifications Engine Oil: API SG or higher service category, SAE 10W-30 or 10W-40...