1988 GMT400-C2500 Manual

The 1988 GMT400-C2500 is a light-duty pickup truck featuring a 5.7L V8 engine, 4-speed automatic transmission, rear-wheel drive, power steering, power brakes, air conditioning, AM/FM radio, and towing capacity up to 7,000 lbs. Below are key sections for specifications, maintenance, operation, troubleshooting, and service procedures.

Vehicle Specifications

Key components: 5.7L V8 engine, 4L60 automatic transmission, independent front suspension, rear leaf springs.

Instrument Panel

Standard gauges and controls for vehicle operation and monitoring.

1. Speedometer: 0-85 mph with odometer and trip meter
2. Tachometer: 0-6000 rpm (if equipped)
3. Fuel gauge: Shows fuel level in 25-gallon tank
4. Temperature gauge: Monitors engine coolant temperature
5. Oil pressure gauge: Monitors engine oil pressure
6. Voltmeter: Monitors charging system voltage
7. Warning lights: Check engine, brake, battery, oil pressure

WARNING! If any warning light illuminates while driving, stop vehicle immediately and investigate cause.

Starting & Operating

Proper procedures for starting, driving, and shutting down vehicle.

1. Before starting: Ensure parking brake is set, transmission in Park
2. Starting: Insert key, turn to ON position, wait for gauge sweep, then start
3. Warm-up: Allow engine to idle for 30 seconds before driving
4. Driving: Shift through PRNDL positions smoothly
5. Parking: Set parking brake, shift to Park, turn key to OFF

CAUTION! Never shift to Park while vehicle is moving. Always use parking brake on inclines.

Routine Maintenance

• Oil Change: Every 3,000 miles or 3 months with 5W-30
• Oil Filter: Replace with every oil change
• Air Filter: Inspect every 12,000 miles, replace as needed
• Spark Plugs: Replace every 30,000 miles
• Coolant: Flush and replace every 30,000 miles
• Transmission Fluid: Change every 30,000 miles
• Brake Fluid: Check level monthly, replace every 2 years
• Tire Rotation: Every 6,000 miles

Fluid Specifications

Access fluid fill points under hood. Engine oil: dipstick near front passenger side.

Capacities: Engine oil: 5 quarts with filter. Coolant: 13 quarts. Transmission: 11 quarts. Fuel: 25 gallons.

Electrical System

12-volt negative ground system with 65-amp alternator and maintenance-free battery.

1. Battery: 12V, 550 CCA, located in engine compartment
2. Alternator: 65-amp output, belt-driven
3. Fuses: Located in fuse block under dashboard
4. Bulbs: Headlights 4651, taillights 2057, dome light 561

Tip: Check battery terminals for corrosion monthly. Clean with baking soda solution if needed.

Brake System

Hydraulic dual-circuit system with power assist. Front disc, rear drum configuration.

1. Brake pedal: Should have firm feel, no sponginess
2. Parking brake: Mechanical lever between seats
3. Fluid level: Check monthly in master cylinder reservoir
4. Pad/shoe inspection: Every 12,000 miles or as needed
5. Rotor/drum inspection: During brake service

WARNING! If brake pedal feels soft or travels to floor, have system inspected immediately.

Cooling System

Pressurized system with radiator, water pump, thermostat, and electric fan.

Maintain proper coolant level in overflow tank. System pressure: 15 psi cap. Thermostat opens at 195°F.

Towing Guidelines

Maximum towing capacity: 7,000 lbs with proper equipment.

1. Use Class III hitch receiver
2. Install transmission cooler for heavy towing
3. Check trailer brakes if over 2,000 lbs
4. Distribute load evenly in trailer
5. Allow longer stopping distances

CAUTION! Never exceed maximum towing capacity. Ensure trailer lights function properly.

Troubleshooting

Service: Consult authorized GM dealer for major repairs. Keep all maintenance records.