Introduction At one time, fi xing an automatic transmission involved taking it apart, cleaning and inspecting the internal com- ponents, and replacing worn parts. While this took skill and attention to detail, it was a relatively simple procedure. Since there were only a few types of automatic transmis- sions, technicians could become profi cient in a short period of time. Many automatic transmission technicians learned by experience, making mistakes and learning from them. Today, it is almost impossible to get started on a career in automatic transmission and transaxle repair without formal training and a great deal of study. Th e modern tech- nician must deal with many diff erent transmissions and transaxle designs. Th e high cost of parts and labor prevents the technician from using trial and error to diagnose a trou- blesome transmission. Today’s technicians must develop the same troubleshooting and repair skills needed in the past, but must also learn to diagnose complex electrical and elec- tronic problems. Automatic Transmissions and Transaxles provides the latest information on the design, construction, diagnosis, service, and repair of the automatic transmissions and transaxles used in late-model vehicles. Th is text has been carefully designed so all pertinent components are identi- fi ed and operating principles are fully explained before troubleshooting, service, and repair are discussed. Each chapter of this text begins with a list of objec- tives that provide focus for the chapter. A list of important technical terms is also presented at the beginning of each chapter. Be sure to look for these terms as you read through the chapters. Th ey will be printed in bold italic type when fi rst used in the body of the chapter and will be defi ned when introduced. Figure references are printed in bold type for ease of identifi cation. Warnings and cautions are pro- vided when the risk of injury or property damage is present. Notes are used to highlight information that supplements the material presented in the body of the text. ASE certifi cation is becoming increasingly important. In a few years, it may be diffi cult to get a job as an automotive technician if you are not certifi ed. Automatic Transmissions and Transaxles is a valuable resource for those preparing for ASE Certifi cation Test A2, Automatic Transmission/ Transaxle. Th e content is correlated to the ASE/NATEF Task List. ASE-type questions at the end of each chapter help students prepare for the questions encountered on the ASE tests. In addition, Chapter 20 is devoted to information about preparing for and taking ASE tests. A Workbook for Automatic Transmissions and Transaxles is available to complement this textbook. Th e workbook contains additional test questions, as well as jobs to help you develop your hands-on service techniques. Th e chapters in the workbook are correlated to those in the textbook. By choosing Automatic Transmissions and Transaxles, you have made a good start in preparing for a career in the fi eld of automotive service and repair. Chris Johanson James E. Duff y 3