1988 Chevy P30 Service Manual

The 1988 Chevy P30 is a step-van chassis platform used for commercial and delivery vehicles, featuring robust construction, reliable powertrain options, and versatile configurations. This service manual covers maintenance procedures, troubleshooting, specifications, and repair guidelines for the P30 chassis, including engine systems, transmission, brakes, electrical, suspension, and body components. Below are key sections for technical specifications, maintenance schedules, repair procedures, and troubleshooting.

1. Vehicle Specifications 2. Maintenance Schedule 3. Engine Systems 4. Transmission & Drivetrain 5. Brake System 6. Electrical System 7. Suspension & Steering 8. Body & Frame 9. Troubleshooting Guide 10. Technical Bulletins

Vehicle Specifications

Key technical data for the 1988 Chevy P30 chassis platform.

Specification	Description
Wheelbase	125-inch, 137-inch, or 157-inch options
GVWR	10,000 to 14,000 lbs depending on configuration
Engine Options	5.0L V8, 5.7L V8, 7.4L V8 gasoline engines
Transmission	3-speed automatic or 4-speed manual
Fuel Capacity	30-40 gallon tank depending on configuration
Brake System	Hydraulic disc front/drum rear with vacuum booster
Suspension	Independent front with leaf spring rear
Electrical	12-volt system with 60-amp alternator
Cooling System	Heavy-duty radiator with engine-driven fan
Exhaust	Single exhaust system with catalytic converter

Maintenance Schedule

Recommended service intervals for optimal performance and longevity.

Every 3,000 miles: Change engine oil and filter
Every 6,000 miles: Inspect brakes, rotate tires, check fluid levels
Every 12,000 miles: Replace air filter, inspect spark plugs
Every 30,000 miles: Change transmission fluid, inspect timing chain
Every 60,000 miles: Replace coolant, inspect fuel system

WARNING! Always use recommended fluids and follow torque specifications. Use jack stands when working underneath vehicle.

Engine Systems

Service procedures for engine components and systems.

Oil Change: Drain oil, replace filter, refill with 5W-30
Tune-up: Replace spark plugs, wires, distributor cap, rotor
Cooling System: Check radiator, hoses, thermostat, water pump
Fuel System: Inspect fuel pump, filter, carburetor adjustments
Ignition System: Set timing, adjust points (if applicable)

CAUTION! Allow engine to cool before opening cooling system. Disconnect battery when working on electrical components.

Transmission & Drivetrain

Automatic Transmission: TH400 3-speed, fluid capacity 10 quarts
Manual Transmission: SM465 4-speed, gear oil capacity 4 pints
Transfer Case: NP205 (4WD models), gear oil capacity 3 pints
Drive Shaft: Two-piece with center support bearing
Rear Axle: Corporate 14-bolt, capacity 4.5 pints 80W-90
U-Joints: Grease every 6,000 miles
Fluid Types: Dexron II for automatic, 80W-90 for manual

Brake System

Hydraulic brake system service and maintenance procedures.

Front Brakes: Disc brakes with single piston calipers, pad replacement procedure. Rear Brakes: Drum brakes with self-adjusting mechanism, shoe replacement. Master Cylinder: Dual reservoir, bench bleeding procedure. Brake Lines: Steel and rubber lines, inspection for corrosion.

Electrical System

12-volt electrical system diagnostics and repair.

Battery: Group 78, 650 CCA, specific gravity check
Alternator: 60-amp output, voltage regulator testing
Starter: Direct drive, solenoid replacement procedure
Wiring: Color-coded diagrams, connector repair
Lights: Headlight aiming, bulb replacement procedures

Tip: Always disconnect battery negative terminal before electrical work. Use circuit tester for diagnostics.

Suspension & Steering

Front and rear suspension components and steering system.

Front Suspension: Independent with torsion bars, ball joint inspection
Rear Suspension: Leaf springs with shock absorbers
Steering Gear: Recirculating ball, adjustment procedures
Alignment Specs: Camber, caster, toe settings
Shock Absorbers: Replacement front and rear

WARNING! Use proper spring compression tools. Never heat suspension components.

Body & Frame

Body structure maintenance and frame inspection.

Frame: Ladder-type construction, inspection for cracks or corrosion. Body Mounts: Rubber isolators, replacement procedure. Doors: Hinge adjustment, latch mechanism service. Seals: Weatherstrip replacement for cargo areas.

Troubleshooting Guide

Symptom	Possible Cause	Corrective Action
Engine won't start	Battery, ignition, fuel system	Check battery voltage, spark, fuel delivery
Poor fuel economy	Tune-up needed, dragging brakes	Replace plugs, filters; inspect brake system
Brake pull	Stuck caliper, contaminated pads	Inspect calipers, replace pads, flush fluid
Electrical issues	Ground connections, alternator	Check grounds, test alternator output
Transmission slipping	Low fluid, worn bands	Check fluid level and condition, adjust bands

Note: Always begin diagnosis with simplest solutions first. Use factory service tools when available.

Service Support: Contact GM technical assistance for complex issues.