Chapter 3 Answers to Review Questions

C L A S S R O O M M A N U A L , P A G E S 7 9 - 8 1

Short Answer Essays 1. “Shift feel” is controlled by the pressure at which each reaction member is applied or released, the rate at which each is pressurized or exhausted, and the relative timing of the apply and release of the members. 2. A typical automatic transmission consists of four basic systems: the torque converter, planetary gearsets, hydraulic system, and reaction members. 3. A vacuum modulator measures engine vacuum to sense the load placed on the engine and the drive train. A vacuum modulator is a load sensing device that increases or decreases fluid pressure in response to a vacuum signal that varies with throttle opening and vehicle load. 4. Shift timing is determined by throttle pressure and governor pressure acting on opposite ends of the shift valve. Shift valves control the upshifting and downshifting of the transmission by controlling the flow of pressurized fluid to the apply devices that engage the different gears. 5. As engine load increases, engine vacuum decreases. 6. Transmissions are equipped with a fluid cooler that prevents the overheating of the fluid, which could result in damage to the transmission. 7. When the engine is operating under heavy load conditions, fluid pressure is raised to increase the holding capacity of a reaction member, and upshifts are delayed. 8. The torque converter engages and disengages the engine’s power to the transmission in relation to engine rpm. The main components of a torque converter are the cover, turbine, impeller, and stator. The cover is connected to the flywheel and transmits power from the engine to the impeller, which allows for torque multiplication and drives the transmission’s oil pump. The turbine is splined to the input shaft and driven by the force of the fluid from the impeller. 9. Valve bodies are normally fitted with three different types of valves: spool valves, check ball valves, and poppet valves. The purpose of these valves is to start, stop, or use movable parts to regulate and direct the flow of fluid throughout the transmission. 10. Reaction members are those parts of an automatic transmission that hold or drive members of the planetary gearset in order to change gears.

Fill-in-the-Blanks 1. Multiple-disc clutches, one-way clutches, friction brakes 2. Turbine, impeller, stator

17 3. Gear, rotor, vane 4. Hub, shell 5. Road, valve body 6. Supply, pressure, operate, lubricate, cool 7. Pressure-regulating, flow-directing 8. Electronically, throttle pressure, vacuum modulator 9. Sense, respond, driver 10. Speed, load, speed

Multiple Choice 1. C 2. D 3. D 4. A 5. C 6. C 7. C 8. B 9. C 10. B

Instructor’s Guide to Accompany Today’s Technician: Automatic Transmissions & Transaxles 3E 18 S H O P M A N U A L , P A G E S 1 1 2 - 1 1 3

ASE-Style Review Questions 1. C 2. A 3. D 4. C 5. B 6. C 7. C 8. D 9. B 10. A

ASE Challenge Questions 1. C 2. A 3. C 4. A 5. B

Instructor’s Guide to Accompany Today’s Technician: Automatic Transmissions & Transaxles 3E 19