Automatic Transmission Hydraulic Components

1. In automatic transmissions, which type of component is used to regulate, direct, and control the pressure and movement of the fluid after it leaves the pump?

Oil coolers Accumulators Valves and hydraulic passages Mechanical linkages

2. Hydraulic valves in an automatic transmission may be used for which of the following applications?

Convert rotary motion to linear motion. Prevent excessive engine vacuum. Act as a pressure relief to relieve excessive pressure. Adjust the crush sleeve on the output shaft.

3. What is the primary characteristic of the control valves used in automatic transmissions that directs flow and pressure only?

They are complex in design and operation. They regulate oil pressure and flow. They are usually very simple in their design and operation. They are always balanced valves controlled by engine vacuum.

4. If the oil cooler or cooler lines become restricted or plugged, a spring-loaded ball valve is forced open to allow fluid to bypass the cooler. In this function, the valve acts as what component?

A pressure relief valve A spool valve A bypass valve A simple hydraulic valve

5. What mechanism is commonly used throughout the hydraulic system to dampen the effects of hydraulic pulses?

Check valves Orifices Spool valve lands Governor weights

6. Which component is most commonly used in an automatic transmission when a valve must interconnect several passages or react to more than one pressure?

Check valve Ball-type relief valve Spool valve Manual valve

7. What feature is machined into the lands of a typical spool valve?

Exhaust ports Inlet ports Cleaning grooves Valve face

8. Pressure relief valves are primarily used to protect the hydraulic system from damage due to excessive pressure. When the pressure builds beyond the tension of the spring, the valve opens and exhausts the fluid to which location?

The oil cooler The governor circuit The sump The manual valve inlet port

9. Check valves are classified as one-way valves that simply connect or disconnect hydraulic passages. When is the check valve forced onto its seat to prevent backflow of oil?

When fluid is flowing through the inlet passage. When the pump pressure is at its maximum. When fluid pressure is applied to the outlet sides of the valve. When the pressure relief valve opens.

10. The manual valve is unique because its position is determined solely by which type of input?

Hydraulic pressure from the governor. Vacuum pressure from the modulator. Mechanical input from the driver (range selector lever). Electrical signal from the PCM.

11. What is the specific functional purpose of the manual valve?

To regulate mainline pressure based on engine speed. To provide a high mainline pressure boost during acceleration. To direct fluid pressure to the various ports within the hydraulic system to control transmission operation. To convert AC voltage from the VSS into a square wave.

12. The manual valve distributes regulated line pressure to apply the various clutch and band servo assemblies. The fluid pressure is allowed to flow only to which circuits?

All ports that are not closed or exhausted. The governor valve, throttle valve, and shift valves only. Only the circuits required for the selected operating range. The mainline pressure boost circuit.

13. What holds the manual valve in each of the operating positions selected by the range selector lever?

The hydraulic pressure supplied by the pump. A vacuum diaphragm and spring assembly. A spring-loaded detent arrangement. The overdrive gate stop.

14. What type of valve is the manual valve classified as, based on its internal design?

Ball-type relief valve Check valve Spool valve Balanced valve

15. In the Park position, what mechanism engages the parking gear (sprag) to lock the output shaft to the case?

The overdrive gate stop A park pawl The detent arrangement The shiftgate lever

16. What is the purpose of the throttle valve (TV) in a transmission hydraulic circuit?

To regulate fluid flow to the governor. To maintain a constant mainline pressure regardless of engine load. To provide pressure that varies with throttle opening or engine load. To act as an on/off switch for the shift solenoids.

17. Throttle valves are regulating (balanced) valves that achieve a regulated (balanced) pressure by controlling which specific component of the valve?

The exhaust port The inlet port (as the controlling restriction) The overdrive gate stop The spring tension

18. Throttle (TV) pressure is directed to the boost valve of the main pressure regulator for what primary purpose?

To reduce the mainline pressure when the vehicle is stationary. To boost line pressure and firm upshifts during vehicle acceleration. To close the exhaust port when the valve is in the closed position. To initiate a downshift (kickdown) for increased economy.

19. Which condition is NOT a driving situation that requires mainline pressure to be increased above the base value?

Engine torque increases due to acceleration. Manual ranges for trailer towing or engine braking. Reverse range operation. Normal cruising at a constant speed and light throttle.

20. When the throttle linkage is moved to the closed throttle position, what is the resulting outlet pressure (TV) directed to the shift valve assemblies?

High pressure equal to line pressure. Pressure equivalent to 3 '' Hg vacuum. 0 psi (zero TV pressure). 30 psi, resulting in maximum shift points.

21. Directing zero TV pressure to the shift valve assemblies during closed throttle operation results in what shifting characteristic?

Firm and aggressive shifts. Delayed upshifts. Minimum shift points. Kickdown for increased acceleration.

22. In a mechanically controlled throttle valve system, when the throttle linkage is moved to Wide Open Throttle (WOT), the high pressure is used to delay upshifts to allow them to correspond with:

The vacuum modulator setting. The lowest possible line pressure. The heavier acceleration. The closed throttle position.

23. Which term has the same meaning as throttle and performs the same functions for transmission operation?

Governor Shift valve Modulator Accumulator

24. The function of the vacuum modulator is to provide a regulated pressure that varies with what external condition?

Atmospheric pressure only. Output shaft speed. Engine manifold vacuum (engine load). Fluid pressure in the shift valve circuits.

25. The spring side of the vacuum modulator canister is connected to a vacuum line source. The force of the spring is opposed by which force?

Atmospheric pressure acting on the diaphragm. Mainline pressure acting on the valve face. Engine manifold vacuum acting on the diaphragm (in the sealed chamber). Centrifugal force from the governor.

26. When engine vacuum is high (closed throttle), the pressure differential moves the diaphragm, allowing the modulator valve to close the inlet port. What is the resulting TV pressure?

High pressure equal to incoming line pressure. A minimum pressure very close to 0 psi. Maximum boost pressure (two to three times the base). Pressure equal to the spring's maximum effective tension.

27. When engine vacuum is low (wide open throttle), the coil spring tension is allowed to move the modulator valve, opening the inlet port. The resulting TV pressure is:

Minimum hydraulic output pressure. High pressure equal to the incoming line pressure. 0 psi to provide minimum shift points. High effective spring tension only.

28. What component is considered a hydraulic speedometer that uses centrifugal force to change mainline pressure and output pressure according to vehicle speed?

Throttle valve Modulator Governor Accumulator

29. Governors are regulating (balanced) valves that use the centrifugal force acting on a weight to produce a regulated output pressure. This pressure is directly proportional to what measurement?

Engine RPM. The rate of rotation (road or vehicle speed). The amount of vacuum in the intake manifold. The hydraulic-assisted spring force.

30. As vehicle speed increases, the governor pressure is used to reduce or cut back which other pressure?

Throttle pressure Auxiliary hydraulic force Mainline pressure Exhaust pressure

31. When a governor valve is fully open, what is the maximum pressure it can produce?

0 psi Twice the mainline pressure Pressures equal to mainline pressure. Pressures equal to the throttle pressure.

32. What is the advantage of using a two-stage governor in automatic transmissions?

It eliminates the need for an accumulator. It ensures 1:1 ratio during Direct Drive. It is designed to provide proper governor pressure throughout all driving ranges. It eliminates the need for an interlock pin.

33. What is the main purpose of governor pressure?

To increase line pressure during acceleration (boost). To lock the torque converter clutch. To control automatic upshifts and downshifts. To hold the park pawl in place.

34. Governor pressure acts upon the shift valves in conjunction with which other pressure to determine when an upshift or downshift should occur?

Mainline pressure Throttle or modulator pressure Accumulator pressure Converter clutch pressure

35. The movement of the shift valve is controlled by pressures that have been regulated by other valves, meaning the shift valve is NOT a:

Spool valve. Switch valve. Regulating (balanced) valve. Hydraulic computer element.

36. Shift valves are referred to as switch valves because they are usually a spool-type valve that acts as a simple:

Open/close door. On/off switch for a hydraulic circuit. Relief valve for excessive pressure. Bypass valve for the cooler circuit.

37. What are the two primary purposes of a shift valve?

Increase line pressure and compensate for centrifugal force. Control upshifting and control downshifting. Regulate mainline pressure and regulate throttle pressure. Disengage the torque converter and lock the planetary gear set.

38. The number of shift valves required in a transmission equals:

The total number of gears. One less than the number of speeds the transmission has. The number of clutches and bands combined. The number of planetary gear sets.

39. In a four-speed transmission, how many shift valves are required, and in what order do they operate?

Two shift valves, operating independently. Four shift valves, operating simultaneously. Three shift valves, operating in progressive order (1-2, 2-3, 3-4). Five shift valves, including the reverse shift valve.

40. How is a shift valve classified when it is directing fluid pressure to apply the desired clutch or band?

Closed Exhausted Open Neutral

41. What is the condition known as when the electronic control system to the transmission becomes disabled (solenoids all turned off)?

Full-time operation Overdrive operation Fail-safe or default Torque steer condition

42. In the fail-safe mode of an electronic transmission, what is the resulting operational state?

The transmission automatically shifts into neutral. The transmission operates in one predetermined range. The torque converter clutch is permanently locked. Maximum line pressure is reduced to 0 psi.

43. Which electronic output device is an electronic pressure regulator that performs the same function as the vacuum modulator in hydraulically controlled transmissions?

Shift Solenoid (SS) Electronic Pressure Control (EPC) Solenoid (or VEM) Torque Converter Clutch (TCC) Solenoid Manual Lever Position Sensor (MLPS)

44. In an EPC solenoid, the duty cycle and current flow are inversely proportional to what measurement?

Vehicle speed Engine coolant temperature Throttle angle Mainline pressure

45. When the throttle angle increases, what change in the EPC solenoid's operation occurs, leading to maximum hydraulic output pressure?

Duty cycle is increased, increasing current flow. Duty cycle is decreased, decreasing current flow. The solenoid is energized to the maximum extent. The solenoid is completely turned off (0.0 amps).

46. If the EPC electrical system fails and current flow is 0.0 amps, what is the resulting hydraulic condition in the transmission?

Minimum line pressure (0 psi) Throttle pressure equals 0 psi Maximum line pressure (default setting) The valve operates at minimum throttle duty cycle

47. What is the sole purpose of the brake switch signal in controlling torque converter clutch (TCC) operation?

To increase line pressure during braking. To disengage the torque converter lockup clutch when the brakes are applied. To apply the clutch brake. To signal the PCM to delay upshifts.

48. The PCM uses the Engine Coolant Temperature (ECT) sensor primarily to control what specific function?

Shift timing and shift feel. Torque converter operation (application). Engine idle speed compensation. Mainline pressure boost.

49. Which two types of solenoids are used to control transmission operation?

Hydraulic and mechanical. On/off and pulse width modulated (PWM). Single-acting and double-acting. Fixed displacement and variable displacement.

50. If a vacuum modulator is replaced, what related sales item is listed in the replacement components table?

Fluid Filter and gasket kit Vacuum hose Sensors