Powershift and Automatic Transmission Control and Shifting Flashcards
1
Q
- The three (3) hydraulic circuits in a basic shift control system are:
a)
b)
c)
A
- a) the clutch application circuit
b) the converter charging circuit
c) the transmission lubrication circuit
2
Q
- Oil flow for transmission control system operation is supplied by _______________________________.
A
- Oil flow for transmission control system operation is supplied by a charging pump that is driven at engine speed.
3
Q
- In a basic hydraulic shift control system, transmission speed and direction changes are made by the:
a) clutch pressure regulator valve.
b) torque converter pressure relief valve.
c) shift selector valve.
d) lubrication pressure relief valve.
A
- c) shift selector valve.
4
Q
- The function of the clutch pressure regulator valve is to __________________.
A
- The function of the clutch pressure regulator valve is to limit the application pressure applied to the transmission clutch pistons.
5
Q
- The circuit that receives oil flow after the clutch application circuit has been satisfied, is the:
a) converter charging circuit.
b) transmission lubrication circuit.
c) governor circuit.
d) modulator circuit.
A
- a) converter charging circuit.
6
Q
- Maximum oil pressure within the torque converter is controlled by __________________.
A
- Maximum oil pressure within the torque converter is controlled by the torque converter relief valve.
7
Q
- Torque converter outlet oil flow is cooled and filtered before it is directed into the __________
circuit.
A
- Torque converter outlet oil flow is cooled and filtered before it is directed into the transmission lubrication circuit.
8
Q
- When towing a machine that is equipped with a powershift or automatic transmission, you must take precautions to prevent the internal components of the
transmission from rotating because ____________.
A
- When towing a machine that is equipped with a powershift or automatic transmission, you must take precautions to prevent the internal components of the transmission from rotating because there is no flow from the transmission charging pump therefore the transmission will be damaged due to lack of lubrication.
9
Q
- Some transmissions are equipped with a scavenging pump whose function is to:
a) provide oil flow to the transmission clutches.
b) remove leakage oil from the transmission case.
c) provide oil flow for transmission lubrication.
d) provide oil flow for transmission cooling.
A
- b) remove leakage oil from the transmission case.
10
Q
- The term clutch modulation refers to ___________________
A
- The term clutch modulation refers to controlling the buildup of pressure in the clutch piston allowing controlled slippage of the clutch discs.
11
Q
- The purpose of modulating the application of transmission clutches is to prevent shift shock.
a) true
b) false
A
- a) true
12
Q
- The two (2) factors that influence the point at which an automatic transmission will shift are:
a)
b)
A
- a) machine ground speed
b) the operator’s demand for power
13
Q
- The function ofthe governor circuit in and automatic transmission is to:
a) apply the transmission clutches.
b) provide transmission lubrication oil flow.
c) provide a hydraulic signal that is proportional to machine ground speed.
d) provide a hydraulic signal that is proportional to throttle position.
A
- c) provide a hydraulic signal that is proportional to machine ground speed.
14
Q
- The hydraulic governor in an automatic transmission operates by balancing the
centrifugal force of the governor flyweights against:
a) spring force.
b) clutch application pressure.
c) modulator pressure.
d) governor pressure.
A
- d) governor pressure.
15
Q
- Some automatic transmissions allow the adjustment of automatic shift points. This is normally accomplished by replacing the shift signal valves with ones of differing areas.
a) true
b) false
A
- b) false; Shift points are normally adjusted by varying shift signal valve spring
force.
16
Q
- The function of the modulator circuit is to:
A
- The function of the modulator circuit is to provide a hydraulic signal pressure that is proportional to the position of the engine throttle. This pressure is used to delay transmission shift points during wide open throttle operation.
17
Q
- If a clutch releases much more quickly than the next clutch is applied during a shift,
the result is:
A
- If a clutch releases much more quickly than the next clutch is applied during a shift, the result is a flare up of engine rpm and a momentary freewheeling of the machine until the next clutch is fully applied
18
Q
- Momentary engine lugging and slowing of machine speed during shifting indicates
that
A
- Momentary engine lugging and slowing of machine speed during shifting indicates that this condition is a result of a releasing clutch that does not fully release before the next clutch is applied.
19
Q
- The shift selector of an electronically shifted automatic transmission consists of a
number of switches that sends ________
signals to the ecu that indicate ___________.
A
- The shift selector of an electronically shifted automatic transmission consists of a number of switches that sends voltage signals to the ECU that indicate the speed and direction desired by the operator
20
Q
- What component of an electronic automatic shift control system performs the same function as the governor in hydraulically controlled systems?
a) the throttle position sensor
b) a speed sensor
c) the shift selector
d) pressure and temperature sensors
A
- b) a speed sensor
21
Q
21. List four (4) functions of the ECU in an electronically controlled shift system. a) b) c) d)
A
- a) control upshifts and downshifts
b) control clutch modulation
c) provide diagnostic information
d) provide a warning to the operator when a malfunction occurs
22
Q
- The output devices that are responsible for causing speed and direction changes are ______.
A
- The output devices that are responsible for causing speed and direction changes are shift solenoids.
