Transfer Case Overhaul . . . . . . . . . . . . . . . . . . 406 Transfer Case Removal | Transfer Case Disassembly | Transfer Case Parts Inspection | Transfer Case Reassembly | Transfer Case Installation Servicing Locking Hubs . . . . . . . . . . . . . . . . . . 415 Chapter 20 Noise, Vibration, and Harshness Service . . . . . . . . . . . . . . . . . . . . . . . . . . 419 Noise, Vibration, and Harshness (NVH). . . . . . . 420 Vibration and Noise | Sources of Vibration and Noise | Harshness | Sources of Harshness | Reducing NVH Diagnosing NVH Complaints . . . . . . . . . . . . . . 422 NVH Test Equipment | Th e Seven- Step Troubleshooting Process | Th e Importance of Follow-Up NVH Complaint Correction. . . . . . . . . . . . . . . . 425 Drive Shaft and CV Axle Vibration Correction | Tire and Rim Vibration Correction | Brake Vibration Correction | Engine Vibration Correction | Harshness Correction | Isolating NVH Signals Chapter 21 ASE Certifi cation . . . . . . . . . . . . . . . . . . 433 ASE Tests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 434 Other ASE Activities | ASE Test Windows Applying for the ASE Tests . . . . . . . . . . . . . . . . 435 Taking the ASE Tests. . . . . . . . . . . . . . . . . . . . . 435 Types of ASE Test Questions. . . . . . . . . . . . . . . 437 One-Part Questions | Two-Part Questions | Negative Questions | Incomplete Sentence Questions Test Results. . . . . . . . . . . . . . . . . . . . . . . . . . . 439 Technician Confi dentiality . . . . . . . . . . . . . . . . 439 Recertifi cation Tests. . . . . . . . . . . . . . . . . . . . . 439 Chapter 22 Career Preparation . . . . . . . . . . . . . . . . 443 Automotive Servicing. . . . . . . . . . . . . . . . . . . . 444 Levels of Automotive Service Positions. . . . . . . 444 Helpers | Installers | Certifi ed Technicians Types of Auto Service Facilities . . . . . . . . . . . . 445 New Vehicle Dealerships | Chain and Department Store Auto Service Centers | Specialty Shops | Independent Shops | Government-Operated Shops Other Opportunities in the Auto Service Industry. . . . . . . . . . . . . . . . . . . . 447 Shop Foreman or Service Manager | Salesperson or Service Advisor | Parts Specialist | Self-Employment Getting a Job . . . . . . . . . . . . . . . . . . . . . . . . . 448 Finding Job Openings | Applying for the Job Appendix A Basic Electricity and Electronics. . . . . . 453 Basic Electrical Theory. . . . . . . . . . . . . . . . . . . 453 Atoms and Electricity | Conductors and Insulators | Electron Flow | Electrical Properties | Direct and Alternating Current | Types of Electrical Circuits | Circuit Defects Electromagnetism . . . . . . . . . . . . . . . . . . . . . . 457 Vehicle Wiring and Electrical Components. . . . 457 Wiring | Wiring Schematics | Circuit Protection Devices | Switches | Solenoids and Relays | Motors | Resistors | Capacitors Vehicle Electronics . . . . . . . . . . . . . . . . . . . . . 461 Semiconductor Materials Vehicle Computers . . . . . . . . . . . . . . . . . . . . . 462 Computer Circuits | Control Loops | Main Computer Sections | Computer Diagnostic Outputs Appendix B Scan Tools . . . . . . . . . . . . . . . . . . . . . . . 465 Scan Tool Purposes . . . . . . . . . . . . . . . . . . . . . 465 Scan Tool Construction and Usage. . . . . . . . . . 465 Rules for Scan Tool Usage | Connecting the Scan Tool | Inputting Vehicle Data | Scan Tool Menu Functions | Reading Diagnostic Trouble Codes | Using the Freeze Frame Data | Using Scan Tools to Clear Trouble Codes | Using Scan Tools to Program the ECM Scan Tool Maintenance . . . . . . . . . . . . . . . . . . 470 Common Scan Tool Problems . . . . . . . . . . . . . 470 Scan Tool Appears to Have No Power | No Data Message Appears on the Scan Tool Display | Scan Tool Displays an Error Message Useful Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . 471 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 476 Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 492 10 Manual Drive Trains and Axles