303B: Torque Converter Fundamentals & Service Flashcards

1
Q

Identify the two major functions of a torque converter

A
  • Torque multiplication
  • Fluid Coupling / Clutch

303B Pg. 3 & 6

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2
Q

Identify two torque converter features that help protect the driveline and/or transmission

A
  • Shock absorption during engagement reduces powertrain stresses
  • Gradual start-up of load reduces stresses on the driveline and/or transmission

303B Pg. 3

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3
Q

Identify the two types of oil flow within a torque converter and the conditions under which each occurs

A
  • Vortex flow occurs when difference in the impeller and turbine speed is greatest
  • Rotary flow occurs when impeller and turbine are close to the same speed

303B Pg. 5

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4
Q

Vortex flow in a torque converter is the greatest when:

A
  • Beggining of converter phase
  • Torque output is the greatest
  • Difference in the impeller and turbine speed is the greatest

303B Pg. 5

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5
Q

Rotary flow in a hydrodynamic drive is greatest when:

A
  • Coupling phase
  • Impeller and turbine spinning close to same speed
  • Torque output is the lowest

303B Pg. 5

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6
Q

Identify the three main torque converter elements

A
  • Impeller (Drive member)
  • Stator (Reactionary member)
  • Turbine (Driven member)

303B Pg. 8

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7
Q

The purpose of the torque converter stator is to:

A

Change the direction of oil flow to assist in torque miltiplication

303B Pg. 9

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8
Q

The torque converter component that is connected to the transmission input shaft is the:

A

Turbine

303B Pg. 8

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9
Q

Is a lockup clutch engaged at low engine RPM to prevent torque converter slippage during periods when high torque output is required? T/F

A

False
Is activated when at high speeds and low torque demands. Helps acheive a 1:1 drive ratio for fuel efficiency.

303B Pg. 11

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10
Q

The purpose of a torque converter lockup clutch is to:

A

Increase efficiency through a 1:1 drive ratio

303B Pg. 11

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11
Q

The clutch discs of a torque converter lockup clutch are connected to:

A

The impeller and turbine

303B Pg. 11

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12
Q

The term phase refers to what in a torque converter?

A

Converter - Vortex flow, high torque, low speeds
Coupling - Rotary flow, low torque, high speeds
Lockup - Locked clutch, 1:1 drive ratio

303B Pg. 12

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13
Q

Maximum torque converter output torque occurs when:

A

The turbine is stopped and the impeller is turning at maximum rpm

303B Pg. 12

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14
Q

The stator in a torque converter is also called a:

A

Reactionary Member

303B Pg. 9

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15
Q

Torque converter temperature sending units are usually located on:

A

The converter oil output port

303B Pg. 18

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16
Q

In a torque converter, the highest torque output is produced in the variable vane stator when the vanes are in what position?

A

Open position

303B Pg. 16

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17
Q

In a torque converter, when the torque demand is low, what position are the vanes in on a variable vane stator?

A

Closed position

303B Pg. 16

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18
Q

What four functions does the transmission reservoir serve?

A
  • Stores oil
  • Cools oil
  • Settles out contamination
  • De-aerates

303B Pg. 16

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19
Q

Is a torque converter oil cooler mounted on the converter outlet or inlet?

A

To the converter outlet

303B Pg. 17

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20
Q

What does the torque converter pressure regulating valve do?

A
  • Maintains working pressure within the torque converter
  • Prevents cavitation and aeration
  • Located on the converter oil outlet

303B Pg. 17

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21
Q

What is the maximum temperature that torque converter oil should be allowed to reach?

A

121C (250F)

303B Pg. 18 & 31

22
Q

On units with PTO gears mounted in the torque converter housing, is the housing considered a wet or dry housing?

A

Wet housing

303B Pg. 20

23
Q

Which type of housing (Dry or Wet) is usually used on industrial applications when PTO gears are mounted in the converter housing?

A

Wet housing

303B Pg. 20

24
Q

What are five things you can check the torque converter for when it’s removed for repairs?

A
  • Missing balance weights
  • Cracks
  • Broken welds
  • Broken drive lugs
  • Score marks

303B Pg. 36

25
Q

When pressurizing a torque converter to check for leaks, what pressure should it be tested at?

A

Approximately 70psi (483kPa)

303B Pg. 36

26
Q

When cleaning components of a torque converter, what major precaution should be taken for aluminum parts?

A

Ensure that aluminum components will not be damaged by cleaning solutions or hot tank.

303B Pg. 37

27
Q

When is a gravity drain used with a torque converter?

A

When the torque converter housing is located above the transmission.

303B Pg. 21

28
Q

What are the three functions of a torque divider?

A
  • Automatic clutching
  • Multiplies torque
  • Absorbs power train shock loads

303B Pg. 22

29
Q

Which planetary gear set component is the impeller splined to in a torque divider?

A

Sun gear

303B Pg. 23

30
Q

Which component is the internal gear splined to in a torque divider?

A

Turbine

303B Pg. 23

31
Q

Which component is the output shaft driven by in a torque divider?

A

Planet Carrier

303B Pg. 23

32
Q

In a torque divider, what delivers the oil that is used for torque converter operation and component lubrication?

A

Charge Pump

Driven by the impeller or engine flywheel

303B Pg. 17

33
Q

Torque converters may be installed in the power train in what two locations?

A
  • Engine mounted / Integral design
  • Remote mounted

303B Pg. 28

34
Q

What is a critical concern in a remote mounted torque converter application?

A

Proper driveline alignment.

303B Pg. 29

35
Q

What is the difference between a regulating valve and a relief valve?

A

Regulating Valve
- Sets working pressure

Relief Valve
- Sets maximum system pressure
- Always set higher

303B Pg. 17

36
Q

What are two methods of scavenging in a torque converter/transmission?

A

Gravity Drain - Used when the converter housing is located above the transmission

Scavenging Pump - Used when the converter and transmission are on the same plane

303B Pg. 21

37
Q

What is the term that refers to removing excess oil from the torque converter housing in effort to reduce power loss and heat generation?

A

Scavenging

303B Pg. 21

38
Q

What is the basic construction of a torque divider?

A

Single stage torque converter
Single planetary gear set
Carrier
Converter housing

303B Pg. 23

39
Q

With an idling engine and stalled output shaft, what direction does the internal gear and turbine rotate in a torque divider?

A

Reverse

303B Pg. 25

40
Q

With an engine at wide open throttle and a stalled output shaft, what direction does the internal gear and turbine rotate in a torque divider?

A

Reverse

303B Pg. 26

41
Q

What gear should torque converter stall tests be conducted in?

A

Highest gear available

303B Pg. 31

42
Q

What stall test conditions may indicate potential torqe converter problems?

A

High stall speed - Not multiplyng torque or slipping clutches

Low stall speed - Engine not developing required torque, slipping stator overrunning clutch

Overheating - Cooler, charge pump, oil level high/low

303B Pg. 31

43
Q

When conducting a torque converter stall test, you determine you have a low stall speed. What could cause this?

A
  • Engine not developing the required torque
  • Slipping stator overrunning clutch

303B Pg. 32

44
Q

When conducting a torque converter stall test, you determine you have a high stall speed. What could cause this?

A
  • Torque converter not producing required torque
  • Clutches could be slipping

303B Pg. 32

45
Q

When conducting a torque converter stall test, you determine you have an overheating issue. What could cause this?

A
  • Transmission in too high of a gear
  • Plugged oil cooler
  • Faulty charge pump
  • Oil level too high/low

303B Pg. 32

46
Q

Energy transfer in a fluid coupler is dependent on what three factors?

A

Volume - Physical size of impeller vanes, number of vanes
Velocity - Physical size of converter, speed of impeller, size of vanes
Viscosity - Of oil used in the converter

303B Pg. 2

47
Q

What does the term stages refer to in relation to a torque converter?

A

The number of times the oil strikes the turbine before it returns to the impeller.

Normally classed as the number of turbines.

303B Pg. 13

48
Q

In a torque converter, what is designed into the impeller and turbine that smothes and directs vortex flow?

A

Split guide ring

303B Pg. 6

49
Q

What are the two basic types of stators in a torque converter?

A

Fixed - Does not rotate. Can never achieve rotary flow.
Freewheeling - Has an overrunning clutch for both vortex and rotary flow ability.

303B Pg. 10

50
Q

Under what conditions does a freewheeling stator in a torque converter lock up?

A
  • When turbine speed is less than impeller speed
  • Converter phase

303B Pg. 11

51
Q

Under what conditions does a freewheeling stator in a torque converter rotate freely?

A
  • When turbine and impeller are rotating at appromimately the same speed.
  • Coupling stage
  • When transmission is in neutral

303B Pg. 11