Deck 8: Hydraulic Fundamentals

Question 1

Pascal's law states that if we place fluid in a confined space, pressure will:

A) be transferred equally in all directions inside the space.
B) be higher at the lower end of the space.
C) be lower at the lower end of the space.
D) vary at various points inside the space.

Answer 1

A

Question 2

Tech A says that one benefit of using hydraulic pressure is that it is not affected by leaks in the system. Tech B says that hydraulic pressure is the same in all directions within a closed container. Who is correct?

A) Tech A
B) Tech B
C) Both A and B
D) Neither A nor B

Answer 2

B

Question 3

The hydraulic system of an automatic transmission includes all of the following except:

A) a sump.
B) a filter.
C) a front pump.
D) a gasket.

Answer 3

D

Question 4

Depth filters may be made of:

A) metal.
B) felt.
C) plastic.
D) polyester.

Question 5

Tech A says that one type of front pump is a variable displacement pump. Tech B says that the front pump is turned by the torque converter hub. Who is correct?

A) Tech A
B) Tech B
C) Both A and B
D) Neither A nor B

Question 6

A pressure regulator valve ensures that:

A) minimal clamping pressure is applied on clutches and bands.
B) engine load and rpm do not affect the transmission.
C) the pressures are reduced during cruise, when less clutch and band holding power is needed
D) fluid pressure and line pressure stay uniformly high.

Question 7

Which of these is used to regulate line pressure on computerized transmissions?

A) EPC solenoid
B) Multidisc clutches
C) Check valves
D) Accumulators

Question 8

Tech A says that a mechanical pressure regulator exhausts excess fluid back to the transmission pan. Tech B says that if the transmission pan is removed, the magnet must be replaced. Who is correct?

A) Tech A
B) Tech B
C) Both A and B
D) Neither A nor B

Question 9

When rebuilding a clutch pack, the piston needs to be carefully inspected for:

A) clearance.
B) expansion.
C) contraction.
D) cracks.

Question 10

Tech A says that multi-plate clutches must have a specified amount of clearance when they are installed. Tech B says that there should be no clearance when they are installed because the clutch would slip. Who is correct?

A) Tech A
B) Tech B
C) Both A and B
D) Neither A nor B

Question 11

Tech A says that bands are a type of hydraulic valve. Tech B says that servos are devices used to allow free movement in one direction and lock up in the other direction. Who is correct?

A) Tech A
B) Tech B
C) Both A and B
D) Neither A nor B

Question 12

Which of these valves is directly connected to the gearshift mechanism in the vehicle?

A) Shift valve
B) Manual valve
C) Solenoid valve
D) Check valve

Question 13

Tech A says that spring tension against a spool valve regulates system pressure. Tech B says that a 50% pulse width modulation means the valve is closed 50% of the time. Who is correct?

A) Tech A
B) Tech B
C) Both A and B
D) Neither A nor B

Question 14

Tech A says that park is obtained by mechanically locking one band and one clutch together. Tech B says that spool valves tend to be self-cleaning. Who is correct?

A) Tech A
B) Tech B
C) Both A and B
D) Neither A nor B

Question 15

Which of these is often used in conjunction with check balls and spool valves to restrict fluid flow for timing purposes?

A) Separator plate
B) Accumulator
C) Orifice
D) Pressure regulator valve

Question 16

Tech A says that transmission failures can be caused by failed lip seals preventing full pressure from being applied to the clutches. Tech B says that orifices are designed to speed up the movement of a valve. Who is correct?

A) Tech A
B) Tech B
C) Both A and B
D) Neither A nor B

Question 17

Accumulators are used to:

A) dampen the application of clutches and bands.
B) direct fluid under the proper pressure to the appropriate places in the transmission.
C) regulate line pressure.
D) prevent valve fluctuations.

Question 18

Tech A says that accumulators are used to filter contaminates. Tech B says that accumulators are used to soften clutch engagement. Who is correct?

A) Tech A
B) Tech B
C) Both A and B
D) Neither A nor B

Question 19

A clutch and band application chart helps to:

A) obtain a clearer problem description from the customer.
B) better record the problem on a repair order.
C) identify a problem before you pull the transmission.
D) make a diagnosis without checking the transmission.

Question 20

Tech A says that band and clutch application charts can help to diagnose faults in a transmission. Tech B says that 100 psi (689 kPa) of pressure on a 2-square-inch piston results in 50 lb (23 kg) of force. Who is correct?

A) Tech A
B) Tech B
C) Both A and B
D) Neither A nor B

Question 21

What is another name for an apply chart?

A) Calibration chart
B) Transmission chart
C) Gear selection chart
D) Truth chart

Question 22

To which of the following should a technician compare transmission operation during a test drive in order to help isolate the transmission concern?

A) Clutch application chart
B) Owner's manual
C) Scan tool
D) None of the above

Question 23

Which of the following gear reductions would you get having a smaller input gear with 8 teeth driving a larger output gear with 24 teeth?

A) 1:1 gear reduction
B) 2:1 gear reduction
C) 3:1 gear reduction
D) 4:1 gear reduction

Question 24

Technician A says if a servo piston has approximately 3 square inches (49 square mm) of surface area, and hydraulic pressure of 150 psi (1034 kPapplied to it, then it can deliver approximately 450 pounds (204 kg) of force. Technician B says that the pressure applied would be 50lbs (23 kg) Who is correct?

A) Technician A
B) Technician B
C) Both A and B
D) Neither A nor B

Question 25

Comparing observations made on the test drive to clutch and band apply charts can aid the technician in choosing which additional tests will best help diagnose the failure.

Question 26

Technician A says to obtain a direct drive or 1:1 gear ratio, the transmission locks together any two members of the planetary gear set. Technician B says to obtain reverse in a planetary set, the ring gear is attached to the output shaft and the planet carrier is held stationary. Who is correct?

A) Technician A
B) Technician B
C) Both A and B
D) Neither A nor B

Question 27

Technician A says that band and clutch application charts can help to diagnose faults in transmissions. Technician B says that 100 psi of pressure on a 2-square-inch piston results in 50 lb of force. Who is correct?

A) Technician A
B) Technician B
C) Both A and B
D) Neither A nor B

Question 28

Technician A states that when diagnosing an automatic transmission problem, it is important to first verify the customer complaint by taking the vehicle on a road test, if possible. Technician B states that after one has verified the customer complaint, one should pay attention and document when the problem occurs. Who is correct?

A) Technician A
B) Technician B
C) Both A and B
D) Neither A nor B

Question 29

All of the following are advantages of using the clutch and band application charts EXCEPT:

A) easy diagnosis of the fault.
B) arriving at a better estimate of the cost.
C) determining that it may not be necessary to remove the transmission from the vehicle for repair.
D) determining that the transmission does not need repair.

Question 30

A manufacturer's clutch and band application chart is sometimes referred to as a _______ chart.

A) Data
B) Metadata
C) Truth
D) Reality

Question 31

Using the manufacturer's chart, we can start our diagnosis of a failed transmission:

A) after pulling the transmission.
B) when disassembling the transmission.
C) before pulling the transmission.
D) when draining the transmission fluid.

Question 32

If there is a problem in obtaining park, it could be due to:

A) Forward Clutch
B) Forward Sprag
C) Shift Solenoid
D) Overrun Clutch

Question 33

The vehicle has no reverse but moves forward. The transmission seems to drive forward fine. The transmission holds on deceleration in first. Which of these could cause the problem?

A) A bad 1 2 shift solenoid
B) A bad 2 3 shift solenoid
C) The low reverse clutch
D) The reverse input clutch.

Question 34

Everything seems to be working fine but the vehicle is not going into neutral. Where could the problem be?

A) Forward Clutch
B) Forward Sprag
C) Shift Solenoid
D) Overrun Clutch

Question 35

A transmission has no reverse but seems to drive forward fine. Technician A states that the problem could be with the 2-3 shift solenoid. Technician B states that the problem could be with the 1 2 shift solenoid. Who is correct?

A) Technician A
B) Technician B
C) Both A and B
D) Neither A nor B

Question 36

Technician A says that accumulators are used to filter contaminates. Technician B says that accumulators are used to soften clutch engagement. Who is correct?

A) Technician A
B) Technician B
C) Both A and B
D) Neither A nor B

Question 37

Which of the following are used to dampen the application of clutches and bands by increasing the circuit volume during the shift?

A) Servos
B) Accumulators
C) Orifices
D) Check valves

Question 38

Which of the following hydraulic circuits will usually contain an accumulator to prevent harsh shifts?

A) Clutch and lubrication
B) Brake and clutch
C) Torque converter and cooling
D) Governor and throttle

Question 39

Automatic transmission accumulators are composed of a spring-loaded piston within a bore.

Question 40

Accumulators are used to:

A) dampen the application of clutches and bands.
B) direct fluid under the proper pressure to the appropriate places in the transmission.
C) regulate line pressure.
D) prevent valve fluctuations.

Question 41

Pressurized fluid enters the accumulator, pushing the piston and compressing the accumulator spring. Once the piston is seated against the bottom of the accumulator bore, the clutch or brake being applied receives full line pressure.

Question 42

Technician A says accumulators are devices that cushion and absorb application pressure within the transmission. Technician B says accumulators are composed of a spring-loaded piston within a bore. Who is correct?

A) Technician A
B) Technician B
C) Both A and B
D) Neither A nor B

Question 43

Technician A says placing an accumulator in the hydraulic circuit can allow clutches to apply much more progressively. Technician B says placing an accumulator in the hydraulic circuit can allow a band to apply much more progressively. Who is correct?

A) Technician A
B) Technician B
C) Both A and B
D) Neither A nor B

Question 44

Accumulators in an automatic transmission are being discussed. Technician A says that an accumulator helps progressively apply a clutch or band, eliminating a harsh shift. Technician B says that an accumulator has a piston installed in a bore with a spring, and a gradual increase of fluid pressure is applied against the spring, preventing driveline stress. Who is correct?

A) Technician A
B) Technician B
C) Both technicians A and B
D) Neither technicians A nor B

Question 45

Technician A says that an orifice is a restriction. Technician B says that orifices are used to slow down clutch engagement. Who is correct?

A) Technician A
B) Technician B
C) Both A and B
D) Neither A nor B

Question 46

Which of the following devices delay an apply by restricting the flow of oil in a hydraulic circuit?

A) Check valves
B) Orifices
C) Servos
D) Accumulators

Question 47

Transmission orifices are never used in the passage feeding oil pressure to a clutch or band.

Question 48

The delay provided by a flow control orifice enables the engineers to control the amount of time it takes to apply a given device.

Question 49

Technician A say orifices are often used in conjunction with spool valves to restrict fluid for timing purposes or to prevent valve fluctuations. Technician B says accumulators are used to dampen the application of clutches and bands. Which technician is correct?

A) Technician A
B) Technician B
C) Both A and B
D) Neither A nor B

Question 50

Technician A says precisely sized orifices can be used to control fluid flow in hydraulic circuits. Technician B says an orifice provides no restriction in line with the device being applied. Who is correct?

A) Technician A
B) Technician B
C) Both A and B
D) Neither A nor B

Question 51

Technician A says experienced transmission rebuilders never increase the size of the clutch and band application orifices. Technician B says experienced transmission rebuilders may install different accumulator springs or longer accumulator pistons to produce a firmer, quicker shift. Who is correct?

A) Technician A
B) Technician B
C) Both A and B
D) Neither A nor B

Question 52

Technician A say orifices are often used in conjunction with spool valves to restrict fluid for timing purposes or to prevent valve fluctuations. Technician B says accumulators are used to dampen the application of spool valves and one way clutches. Who is correct?

A) Technician A
B) Technician B
C) Both A and B
D) Neither A nor B

Question 53

A(n) __________ is a precision hole, used in conjunction with check balls to restrict fluid flow.

A) Accumulator
B) Solenoid
C) Orifice
D) Oil passage

Question 54

Technician A says that an orifice is responsible for controlling the flow of hydraulic fluid between the valve body and the transmission. Technician B says that the orifice is sometimes built into the transmission or even the separator plate. Who is correct?

A) Technician A
B) Technician B
C) Both Technicians A and B
D) Neither Technician A nor B

Question 55

Which of the following check valve designs allow two different control devices can share the outlet passage.

A) One-way
B) Two-way
C) Dual
D) Single

Question 56

Two-way check valves commonly use a check ball design.

Question 57

Automatic transmission check valves always use a spring to keep the check ball in place.

Question 58

Technician A says check valves are classified as one-way and two-way in automatic transmissions. Technician B says two-way check valves are often used in the release circuit for application devices. Who is correct?

A) Technician A
B) Technician B
C) Both A and B
D) Neither A nor B

Question 59

Technician A says check valves can be used to regulate maximum pressures within in automatic transmissions. Technician B says one-way check valves are often used in the release circuit for application devices. Who is correct?

A) Technician A
B) Technician B
C) Both A and B
D) Neither A nor B

Question 60

A __________ can be one of two different types: one-way or two-way.

A) solenoid valve
B) spool valve
C) check valve
D) none of the above

Question 61

Technician A says that a one-way check valve allows fluid to flow in one direction, and stop fluid flow in another. Technician B says that a two-way check valve has one inlet port and two exhaust ports. Who is correct?

A) Technician A
B) Technician B
C) Both technicians
D) Neither technician

Question 62

A two-way check valve allows two different control devices to share a common outlet passage.

Question 63

Technician A says that a check ball should be replaced during a rebuild. Technician B says that the area a check ball is located should be inspected for damage. Who is correct?

A) Technician A
B) Technician B
C) Both technicians
D) Neither technician

Question 64

Technician A says that all check balls are the same size in a transmission. Technician B says that some transmissions can use many different sizes of check balls, and should always be installed in the correct position. Who is correct?

A) Technician A
B) Technician B
C) Both technicians
D) Neither technician

Question 65

How can spool valves of an automatic transmission be moved or positioned?

A) Manually
B) By spring pressure
C) By hydraulic pressure
D) All of the above

Question 66

The lands are the larger part of a spool valve that fits with minimal clearance into the bore to prevent fluid from flowing around the valve.

Question 67

Which of the following is the name used for the larger end of the spool valve?

A) Lands
B) Valleys
C) Grooves
D) Minor diameters

Question 68

Technician A says spool valves have lands and valleys that are used to block or allow the flow of transmission fluid. Technician B says an automatic transmission uses spool valves, solenoids, and check valves to direct fluid flow. Who is correct?

A) Technician A
B) Technician B
C) Both A and B
D) Neither A nor B

Question 69

Technician A says a shift valve is a spool valve with multiple lands. Technician B says moving the shift lever in the cabin causes the manual valve to move and allows line pressure to flow into the appropriate hydraulic circuit. Which tech is correct?

A) Technician A
B) Technician B
C) Both A and B
D) Neither A nor B

Question 70

What are the larger diameter sections of a spool valve called?

A) Lands
B) Valleys
C) Ridges
D) Grooves

Question 71

Technician A says the spool valve got its name because of its resemblance to the spool that thread or fishing line comes on. Technician B says that with a spool valve, the clearance between the land and the bore must be just great enough to prevent the valve from sticking as it moves back and forth.

A) Technician A
B) Technician B
C) Both A and B
D) Neither A nor B

Question 72

Technician A says that a spool valve can be positioned manually by springs or by hydraulic pressure. Technician B says that spool valves can have multiple lands with different diameters. Who is correct?

A) Technician A
B) Technician B
C) Both technicians
D) Neither technician

Question 73

If a transmission has failed, debris may become lodged in the spool valves requiring the entire valve body to be disassembled and cleaned.

Question 74

Technician A says that the sharp corners on a spool valve give it a self-cleaning action. Technician B says that due to the very close clearances, any damage will make the spool valve unusable. Who is correct?

A) Technician A
B) Technician B
C) Both technicians
D) Neither technician

Question 75

Which of the following is used to move a shift valve to achieve an upshift in an automatic transmission?

A) Governor pressure
B) Line pressure
C) Throttle or modulator pressure
D) Springs

Question 76

Technician A says pressure-regulated valves are similar to line pressure regulation valves except these valves reduce line pressure to suit specific components. Technician B says shift valves are spool valves that direct the flow of hydraulic oil to a clutch or band upon upshift. Who is correct?

A) Technician A
B) Technician B
C) Both A and B
D) Neither A nor B

Question 77

How can spool valves of an automatic transmission be moved or positioned?

A) Manually
B) By spring pressure
C) By hydraulic pressure
D) All of the above

Question 78

Which of the following is the name used for the larger end of the spool valve?

A) Lands
B) Valleys
C) Grooves
D) Minor diameters

Question 79

Technician A says spool valves have lands and valleys that are used to block or allow the flow of transmission fluid. Technician B says an automatic transmission uses spool valves, solenoids, and check valves to direct fluid flow. Who is correct?

A) Technician A
B) Technician B
C) Both A and B
D) Neither A nor B

Question 80

Technician A says a shift valve is a spool valve with multiple lands. Technician B says moving the shift lever in the cabin causes the manual valve to move and allows line pressure to flow into the appropriate hydraulic circuit. Which tech is correct?

A) Technician A
B) Technician B
C) Both A and B
D) Neither A nor B