1. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Chapter 41 Automatic Transmissions and Transaxles

2. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Selects gear ratios according to engine speed, power train load, vehicle speed, and other operating factors Most have four speeds with an overdrive fourth gear Many have five, six, and up to eight speeds Automatic Transmissions and Transaxles

3. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Torque Converter A fluid clutch or coupling that transfers torque from the engine to the transmission Automatically engages and disengages power from the engine in relation to RPM

4. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

5. Torque Converter (Cont.) At idle, there is not enough fluid flow for power transfer As RPM increases, fluid flow is sufficient to transmit engine power

6. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Torque Converter Internal Parts

7. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Torque Converter Components Impeller or Pump Assembly – Receives power from the engine

8. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Torque Converter Components Turbine – Transfers power to the transmission main shaft

9. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Torque Converter Components Stator – Is the torque multiplier Overrunning clutch – Allows the stator to turn in only one direction

10. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Basic Operation Transmission fluid is the medium to transfer energy The faster the impeller rotates, the greater energy the fluid has to transfer The fluid leaving the impeller acts on the turbine The turbine drives the transmission input shaft

11. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

12. Types of Oil Flow Rotary Flow – Oil flow around the circumference caused by rotation of the torque converter on its axis Vortex Flow – Oil flow from the impeller to the turbine and back to the impeller Coupling point is when turbine speed approaches impeller speed

13. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

15. Keeps the stator from rotating when driven in one direction The stator is locked when the there is a difference between the turbine and impeller speeds Overrunning Clutch

16. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

18. Lockup Torque Converter Eliminates the 10% slip between the impeller and turbine Improves fuel economy Reduces operational temperature Most torque converter clutches (TCC) use electronically controlled hydraulic pistons

19. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Lockup Clutch

20. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Knowledge Check Technician A says the overrunning clutch is part of the stator. Technician B says the overrunning clutch is part of the lockup clutch. Who is correct?

21. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Planetary Gears Used to transfer power and multiply torque Compound gearsets spread the load over more teeth for increased strength and to obtain the largest number of gear ratios Planetary carrier may be cast iron, aluminum, or steel

22. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Planetary Gears (Cont.)

23. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Ring Gear (Annulus) – Has internal teeth Sun Gear – Is located in the center of the assembly Planetary Carrier – Holds the planetary pinion gears Planetary Gear Components

24. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Planetary Gearset

25. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. When the planetary carrier is the input, an overdrive condition is produced When the planetary carrier is the output, an underdrive condition is produced When the planet carrier is held, reverse gear is produced Planetary Gear Operation

26. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Simpson – Has two separate planetary gearsets with a common sun gear Ravigneaux – Has two separate sun gears, two separate planetary gears, and a common ring gear Types of Compound Gearsets

27. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Simpson Gearset

28. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Ravigneaux Gearset

29. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Planetary Gearsets in Tandem Some transmissions use two simple planetary gearsets in series Gearset members are not shared Each member has a holding device

30. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Lepelletier System Used on some six, seven, eight, and nine speed transmissions Many are more compact than most four- and five-speed automatics Connects a simple planetary gearset to a Ravigneaux gearset The simple gearset is used as the input

31. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Nonplanetary Gearset Type – Uses constant mesh gears similar to a manual transmission Continuously Variable Type (CVT) – Has no fixed forward speeds – Uses belts and pulleys to provide variable ratios Other Transmission Designs

32. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Honda Nonplanetary Transaxle

33. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. CVT Transmission

34. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

35. CVT Controls Controls consist of the TCM, input sensors, and solenoids A shift control valve controls pressure applied to the drive and driven pulleys

36. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Planetary Gear-Based CVTs Used in Toyota and Ford hybrid vehicles Contains the motor/generators and planetary gearset Used in the 2Mode HEV transmission

37. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Knowledge Check What are the three gears the make up a planetary gearset?

38. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Planetary Gear Controls Certain planetary components must be held while others must be driven Planetary control refers to transmission bands, servos, and clutches

39. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Bands – Are typically used as a holding device Servos – Are used to apply the band Multiple Friction Disc Assemblies – Are used to hold or apply Apply Devices

40. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Transmission Bands A braking assembly positioned around a stationary or rotating drum or carrier

41. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Transmission Servos Covert hydraulic pressure into a mechanical force that applies a band Simple servos are released by spring pressure Compound servos are released and held by fluid pressure

42. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Typical Simple Servo

43. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Transmission Clutches Able to hold and drive planetary gear members Overrunning clutches are used to hold or drive members of the gearset Both sprag and roller overrunning clutches are used

44. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Overrunning Clutches – Can be used to hold or apply members of the gearset – Are typically used as a holding device Apply Devices (Cont.)

45. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

46. Multiple-Disc Clutches A series of friction discs and steel plates used to transmit torque or apply braking force Internal teeth mesh with clutch hub External teeth mesh with internal splines in transmission housing or clutch drum

47. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

49. Bearings are used to reduce wear and friction – Most either slide or roll against the surface Bushings are pressed into place – Support rotating parts, guide parts, and control fluid flow Thrust washers may act as a bearing and a spacer to control endplay Bearings, Bushings, and Thrust Washers

50. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Sliding Bearings – Thrust washers – Bushings Roller Bearings – Torrington – Tapered Ball Bearings Bearing Types

51. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Typical Bearing Locations

52. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Bushing Locations

53. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Torrington Bearing

54. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Snaprings Both internal and external types are used Internal snaprings hold servo and clutch assemblies together May also be used to adjust clearances

55. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Gaskets and Seals Gaskets – Seal two parts together or prevent fluid flow – Classified as either hard or soft gaskets Seals – Used to seal fluid around valves, shafts, and other moving parts

56. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Static – Is used between two parts that do not move Dynamic – Is used between two parts that move with either rotating or reciprocating motion Positive – Prevents all fluid leakage Non-positive – Allows a controlled amount of leakage – Is used to lubricate a moving part Seal Classifications

57. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Typical Seal and Bearing Locations

58. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Metal Sealing Rings Used where some leakage is acceptable Made of cast iron, nylon, or Teflon

59. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Final Drive Assemblies Transmit transaxle output to the differential section Four common configurations: – Helical gear – Planetary gear – Hypoid gear – Chain drive

60. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Chain Final Drive

61. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Knowledge Check Which of the following is NOT a type of apply device? – Overrunning clutch – Band – Multidisc clutch – Thrust bearing

62. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Hydraulic System The fluid operates, lubricates, and cools the transmission The pump is the source of all fluid flow – Pressure - regulating valves change fluid pressure to control shift quality and shift points – Flow - directing valves send to fluid to the correct apply device for gear changes

63. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Fluid reservoir – Oil pan Pressure source – Pump Vent – Necessary to draw fluid into the pump Transmission cooler – Removes excessive heat Control valves – Valve body Output devices – Apply devices Hydraulic System Elements

64. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

65. Functions of ATF Cools the transmission Cleans internal parts ATF under pressure forces valves to move Used to operate clutches and other apply devices

66. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Reservoir Stores the ATF The oil pan stores fluid in the automatic transmission

67. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Venting The case must have a vent to atmospheric pressure The vent allows pressure to dissipate from heat buildup

68. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Transmission Coolers Remove heat from the ATF May be incorporated into the radiator May have separate cooler Lines connect the transmission and cooler

69. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Valve Body Distributes and controls pressurized fluid throughout the transmission Made of two or three main components – Valve body – Separator plate – Transfer plate

70. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

71. Check ball valves Poppet valves Spool valves

72. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Oil Pump Driven by the drive hub of the torque converter Gear and vane-type pumps are common Variable displacement pumps used in some transmissions

73. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Governor Assembly Used to signal upshift or downshift Engine load may delay governor signal

74. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Pressure Boosts Under heavy loads, fluid pressure must be increased to increase holding capacity Engine load can be monitored electronically or by throttle valve pressure Older systems used a vacuum modulator to sense engine vacuum

75. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. MAP Sensor Used to monitor engine load Increased engine load requires changes in transmission operation

76. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Kickdown Valve Downshifts when the driver quickly presses the throttle wide open Older vehicles use a kickdown cable Modern vehicles use TP sensor input

77. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

78. Shift Quality Shift feel is controlled by the pressure at which each hydraulic member is applied or released Timing between band and clutch application to prevent engine flare-up or clutch and band slippage

79. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Shift Timing Determined by throttle pressure and governor pressure acting on opposite sides of the shift valve

80. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Gear Changes Gear changes occur either automatically or at the command of the driver The transmission cannot shift into park, reverse, or neutral by itself

81. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Park/Neutral When park is selected, the park pawl or lever engages the park gear The manual shift valve blocks fluid flow to the clutches and bands Fluid flows to cool the transmission

82. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Reverse The manual shift valve allows fluid to flow to the low/reverse band The front clutch locks, the sun gear becomes the input The ring gear becomes the output

83. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Drive Range Front clutch engages The shift valve controls upshifting into higher gears Once governor pressure is great enough, upshifting will occur

84. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Automatic Downshifting Downshifting occurs when governor pressure decreases Can also occur with throttle pressure overcomes governor pressure