tailieunhanh - FUNDAMENTALS OF AUTOMATIC TRANSMISSIONS

When the ring gear or sun gear is held in a fixed position, and either of the other members is an input member, the output gear rotational direction is always the same as the input gear rotational direction. When the internal teeth of the ring gear turns clockwise, the external teeth of the pinion gears walk around the fixed sun gear while rotating clockwise. This causes the carrier to rotate at a reduced speed | Section 1 FUNDAMENTALS OF AUTOMATIC TRANSMISSIONS Lesson Objectives 1. Compare the function of automatic transmission systems of front- and rear-wheel drive transmissions. 2. List the three major component systems used in Toyota automatic transmissions which a. Transfer torque from the engine. b. Provide varying gear ratios. c. Regulate shift quality and timing. 3. Identify the three types of holding devices used in Toyota automatic transmissions. Automatic Transmissions - Course 262 Section 1 Types of Automatic Transmissions Automatic transmissions can be basically divided into two types those used in front-engine front-wheel drive FF vehicles and those used in front-engine rear-wheel drive FR vehicles. Transmissions used in front-wheel drive vehicles are designed to be more compact than transmissions used in rear-wheel drive vehicles because they are mounted in the engine compartment. They are commonly referred to as a transaxle. Automatic Transmission Types The basic function and purpose for either front or rear drive automatic transmissions are the same. The differential is an integral part of the front-wheel drive transmission whereas the differential for the rear-wheel drive transmission is mounted externally. The external differential is connected to the transmission by a driveshaft. The basic function and purpose for either front or rear drive automatics are the same. They share the same planetary gear train design which is used in all Toyota automatic transmissions and the majority of automatics in production today. 2 TOYOTA Technical Training FUNDAMENTALS OF AUTOMATIC TRANSMISSION The automatic transmission is composed of three major components Torque converter Planetary gear unit Hydraulic control unit For a full understanding of the operation of the automatic transmission it is important to understand the basic role of these components. The torque converter provides a means of power transfer from the engine to the input shaft of the transmission. It .