1988 GMC 2500 5.7L Sierra Repair Manual PDF 1GTFC24KXJE500812

The 1988 GMC 2500 5.7L Sierra is a heavy-duty pickup truck featuring a 5.7L V8 engine, 4-wheel drive capability, automatic transmission, and VIN 1GTFC24KXJE500812. This comprehensive repair manual covers engine systems, transmission, brakes, suspension, electrical systems, steering, cooling, and maintenance procedures specific to this model year and configuration. Below are key sections for specifications, maintenance schedules, troubleshooting, and repair procedures.

1. Vehicle Specifications 2. Maintenance Schedule 3. Engine Systems 4. Transmission & Drivetrain 5. Brake System 6. Suspension & Steering 7. Electrical System 8. Cooling System 9. Fuel System 10. Troubleshooting Guide 11. Safety Precautions

Vehicle Specifications

Key specifications for 1988 GMC 2500 5.7L Sierra with VIN 1GTFC24KXJE500812.

Specification	Details
Engine	5.7L V8 (350 CID) TBI
Horsepower	210 hp @ 4000 RPM
Torque	300 lb-ft @ 2800 RPM
Transmission	4-speed automatic (TH400)
Drivetrain	4WD with transfer case
Fuel System	Throttle Body Injection (TBI)
Fuel Capacity	34 gallons
GVWR	8,600 lbs
Brakes	Front disc, rear drum
Suspension	Independent front, leaf spring rear

Maintenance Schedule

Recommended maintenance intervals for optimal performance.

Oil Change: Every 3,000 miles or 3 months
Filter Replacement: Air filter every 15,000 miles, fuel filter every 30,000 miles
Tune-up: Spark plugs every 30,000 miles
Brake Inspection: Every 10,000 miles
Coolant Flush: Every 30,000 miles or 2 years
Transmission Fluid: Every 30,000 miles

WARNING! Always use recommended fluids and follow torque specifications.

Engine Systems

5.7L V8 engine repair and maintenance procedures.

Engine Removal: Disconnect battery, drain fluids, remove accessories
Cylinder Head: Torque sequence 65 ft-lbs in proper pattern
Timing Chain: Replace at 100,000 miles or if slack exceeds specification
TBI System: Fuel pressure should be 9-13 PSI
Ignition System: HEI distributor with 0.045" spark plug gap

CAUTION! Allow engine to cool before working on cooling system components.

Transmission & Drivetrain

Automatic Transmission: TH400 3-speed with lock-up torque converter
Transfer Case: NP208 with 2WD/4WD selection
Front Differential: 8-lug 10-bolt with 3.73 ratio
Rear Differential: Corporate 14-bolt with 3.73 ratio
Drive Shafts: Two-piece with center support bearing
U-Joints: Greaseable, inspect every 15,000 miles

Brake System

Hydraulic brake system maintenance and repair.

Front Brakes: Disc brakes with single piston calipers, rotor thickness 1.245" minimum

Rear Brakes: Drum brakes 13" x 2.5", adjust every 15,000 miles

Master Cylinder: Dual reservoir, bench bleed before installation

Brake Fluid: DOT 3, replace every 2 years

Suspension & Steering

Front independent torsion bar suspension, rear leaf springs.

Front Suspension: Upper/lower control arms, torsion bars, stabilizer bar
Steering: Recirculating ball, power steering pump pressure 1200-1500 PSI
Ball Joints: Check for play every 15,000 miles
Shock Absorbers: Replace if leaking or poor damping

Tip: Always support vehicle properly with jack stands when working underneath.

Electrical System

12-volt negative ground system with 94-amp alternator.

Battery: Group 78, 650 CCA minimum
Alternator: 94-amp output, test voltage 13.5-14.5 volts
Starter: Direct drive, 1.4 kW
Fuse Panel: Under dash, includes circuit breakers
Wiring: Color-coded schematics included in manual

WARNING! Disconnect battery before performing electrical work.

Cooling System

Pressurized cooling system with 18 PSI radiator cap.

Component	Specification
Radiator	Copper/brass, 26" width
Water Pump	Cast iron, belt driven
Thermostat	195°F opening temperature
Coolant Capacity	16 quarts with heater
Fan Clutch	Thermal, check for resistance when cold

Fuel System

Throttle Body Injection (TBI) fuel delivery system.

Fuel Pump: In-tank, 12-15 PSI pressure

Injectors: Two, flow rate 61 lb/hr at 10 PSI

Fuel Filter: Replace every 30,000 miles

TBI Unit: Contains fuel pressure regulator and injectors

Troubleshooting Guide

Symptom	Possible Cause	Corrective Action
Engine won't start	Fuel pump, ignition, battery	Check fuel pressure, spark, battery voltage
Rough idle	Vacuum leak, dirty injectors	Inspect vacuum hoses, clean TBI unit
Transmission slipping	Low fluid, worn bands	Check fluid level and condition
Brake pulling	Stuck caliper, contaminated pads	Inspect calipers, replace pads
Electrical issues	Bad grounds, alternator	Check ground connections, test alternator

Reset: Disconnect battery for 30 minutes to reset ECU.

Safety Precautions

Always follow safety procedures when working on vehicles.

Use jack stands - never work under vehicle supported only by jack
Disconnect battery before electrical work
Wear safety glasses and gloves
Use proper tools and torque specifications
Work in well-ventilated area

Emergency: Keep fire extinguisher nearby when working with fuel system.