Deck 44: Four- and All- Wheel Drive

Question 1

A four-wheel drive vehicle requires four drive shafts.

Answer 1

False

Question 2

The interaxle differential on an AWD vehicle cannot be locked when the vehicle is driven on dry pavement.

Answer 2

True

Question 3

Front drive axle shafts used on a 4WD vehicle require U-joints or CV joints.

Answer 3

True

Question 4

In a part-time four wheel drive systems, 4WD [4 hi or 4 lo] should not be selected when the vehicle is traveling on dry surfaces.

Question 5

All-wheel drive vehicles may use a viscous clutch, rather than a transfer case, to drive the axle with low tractive effort.

Question 6

An interaxle differential lowers performance in poor traction conditions.

Question 7

All-wheel drive vehicles may be switched to two-wheel drive by activating the mode switch.

Question 8

An automatic all-wheel drive [AWD] system supplies power to all four wheels at all times.

Question 9

Some AWD vehicles have a third differential, instead of a transfer case or viscous clutch.

Question 10

The differential lock in an AWD-equipped vehicle can be used at any time.

Question 11

A vacuum leak could prevent a vehicle from engaging 4WD.

Question 12

The TCM [transmission control module] controls the application of the viscous clutch in a transfer case.

Question 13

Most passenger cars with 4WD are designed for the rigors of off-road driving, in which clearance over rocks and debris is needed.

Question 14

Some 4WD vehicles with automatic locking hubs can become stuck in a situation where they need traction at the front wheels to get unstuck, but because the hubs disengage the front wheels in reverse, the vehicle is incapable of moving.

Question 15

Many AWD vehicles are based on FWD vehicles and do not have a separate transfer case.

Question 16

Most all-wheel drive vehicles are based on an RWD platform.

Question 17

Full-time 4WD vehicles require locking hubs at the front wheels.

Question 18

A typical four-wheel drive truck is equipped with a longitudinally based engine, a manual or automatic transmission, and a transfer case.

Question 19

A passenger car equipped with a 4WD system weighs approximately 170 pounds more than a similar 2WD car.

Question 20

Usually the drive chain is replaced if the transfer case is being serviced.

Question 21

Front hubs on 4WD vehicles are being discussed. Technician A says front hubs lock automatically. Technician B says front hubs must be manually engaged. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 22

The Haldex clutch in the all-wheel drive automatic transaxle takes the place of the ______.

A) transmission
B) reduction gears
C) torque converter
D) interaxle differential

Question 23

Technician A says the transfer case splits torque from the transmission to the front and rear axles. Technician B says viscous clutch units can be overhauled. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 24

Technician A says an all-wheel drive vehicle uses a differential at both axles. Technician B says some four-wheel drive vehicles use an interaxle differential. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 25

Which of the following components is NOT part of a viscous clutch assembly?

A) sealed drum
B) hydraulic piston
C) externally splined steel plates
D) internally splined steel plates

Question 26

Technician A says viscous couplings are electronically controlled. Technician B says Haldex clutches are electronically controlled. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 27

Viscous clutches are being discussed. Technician A says if the clutch malfunctions, it must be replaced. Technician B says viscous clutch fluid must be checked periodically. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 28

The following should be done before removing the transfer case EXCEPT:

A) disconnect the front and rear drive shafts
B) disconnect the speed sensor connection
C) remove and label all electrical connectors
D) remove the chain cover and rear cover assemblies

Question 29

In an automatic AWD vehicle, normally one axle receives all the torque; when slippage occurs, 50 percent of the torque can be sent to the other axle by _____ means.

A) hydraulic
B) mechanical
C) electrical
D) all answers are correct

Question 30

Two technicians are discussing transfer case shifting mechanisms. Technician A says the transfer case range is controlled by a shifter lever and mechanical linkage. Technician B says the transfer case range is controlled electrically by a switch on the dash and an electric motor on the case. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 31

Which of the following is not a routine transfer case servicing procedure?

A) checking the fluid level
B) adjusting the chain tensioner
C) necessary visual inspections for leaks and damage
D) inspecting shift linkage for wear and binding

Question 32

Interaxle differential construction is being discussed. Technician A says some are designed with a multiple-disc clutch pack. Technician B says cone brake clutches are not used. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 33

Technician A says an interaxle differential can lower performance in poor traction conditions. Technician B says many 4WD vehicles use an interaxle differential in the transfer case to eliminate driveline windup during turns. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 34

Two technicians are discussing tires for 4WD vehicles: Technician A says narrow tires tend to cut through snow and water rather than hydroplane over it. Technician B says 4WD and AWD systems allow the use of tires narrower than those used on 2WD vehicles. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 35

Technician A says a vacuum motor engages some 4WD front axles. Technician B says an electrical motor engages some 4WD front axles. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 36

Four-wheel drive operation modes are being discussed. Technician A says 4-low, as compared to 4-high, increases wheel torque. Technician B says 2-low is available on most 4WD vehicles. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 37

In a viscous clutch, when the silicone fluid is heated, it ______.

A) becomes a very thin fluid
B) boils to a vapor
C) thickens to a solid mass
D) stiffens

Question 38

Under what conditions should the interaxle differential be locked?

A) on dry roads at highway speeds
B) on dry roads at low speeds
C) when driving in snow or off road at high speed
D) when driving in snow or off road at low speed

Question 39

Technician A says some AWD systems have a center differential. Technician B says some AWD vehicles have a viscous clutch. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 40

Which 4WD transfer case shift position should be used for climbing steep hills when driving off-road?

A) 2-high
B) 2-low
C) 4-high
D) 4-low

Question 41

Front axle disconnect systems are being discussed. Technician A says the systems use a vacuum motor to disengage and engage the right side axle shaft from the differential. Technician A says an electric motor is used to engage and disengage the axle. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 42

Two technicians are discussing the difference between 4WD and AWD. Technician A says AWD does not have an interaxle differential lockout. Technician B says AWD does not have a low range. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 43

Technician A says in a full-time AWD transmission/transfer case, the hydraulic clutch that controls slippage in the 4WD system is controlled by inputs from the ABS wheel speed sensors. Technician B says some full-time AWD transfer cases can lock the differential so that the front and rear driveshafts must turn at the same speed. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 44

Locking hubs are generally found on ______.

A) full-time all-wheel-drive vehicles
B) automatic all-wheel-drive vehicles
C) newer SUVs and pickup trucks with full-time 4WD
D) older SUVs and pickup trucks with part-time 4WD

Question 45

If the 4WD indicator light is flashing on and off, ______.

A) there is a short in the indicator circuit
B) the 4WD actuator motor is faulty
C) the manual locking hubs are in the unlocked position
D) a fault code is stored in the 4WD system

Question 46

Interaxle differentials are being discussed. Technician A says the interaxle differential is located inside the front axle housing. Technician B says the interaxle differential is located inside the rear axle housing. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 47

A ratcheting sound from an automatic locking hub may be caused by ______.

A) worn U-joint in front drive shaft
B) misadjusted transfer case linkage
C) the hub on the opposite side of the axle not disengaging
D) a seized 4WD actuator motor

Question 48

Many transfer cases require _____ lubricants as used in differentials and in some manual transmissions.

A) extreme pressure (EP)
B) synthetic
C) low viscosity
D) polycarbonate

Question 49

Automatic locking hubs are unlocked when ______.

A) the ground for the lock actuator solenoid is removed
B) hydraulic pressure on the apply drum is released
C) vacuum is applied to the release servo
D) the vehicle is driven slowly in reverse 2WD mode

Question 50

Technician A says the viscous clutch is filled with silicone fluid. Technician B says the viscous clutch solenoid is controlled by inputs from the wheel speed sensors. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 51

Technician A says part-time 4WD vehicles do not have an interaxle differential. Technician B says part-time 4WD vehicles do not have a transfer case. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 52

Technician A says mismatched tire sizes can cause transfer case noise. Technician B says incorrect tire inflation pressure can cause transfer case noise. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 53

Part-time 4WD is found on what type of vehicle?

A) full-size pickup truck
B) FWD passenger-car-based SUV
C) RWD truck-based SUV
D) all answers are correct

Question 54

Technician A says the transfer case uses a chain to transfer torque from the transmission to the front driveshaft. Technician B says the transfer case uses spur or helical cut gearsets to transfer torque to the front driveshaft. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 55

Technician A says AWD systems are based on FWD systems that use a viscous clutch, center differential, or transfer clutch to transfer power from the transaxle to a rear driveline. Technician B says an AWD system is based on RWD systems that use a transfer case, front drive shafts, and front axle assemblies to drive the front wheels. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 56

Technician A says on-demand 4WD systems are controlled by the PCM/TCM. Technician B says when slip is detected at the rear wheels, the duty cycle to the output clutch at the transfer case is decreased. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 57

Which of the following components is (are) NOT found in a transfer case?

A) drive chain
B) shifter forks
C) blocking rings
D) planetary gearset

Question 58

The wheel bearing locknuts on most 4WD vehicles require the use of a ______.

A) four- or six-pronged special socket
B) T-60 torx socket
C) 12 mm Allen socket
D) compound impact driver

Question 59

What will happen if the manual locking hubs remain in the 4WD or locked position when the vehicle is driven in 2WD mode?

A) Fuel economy will be reduced
B) Driveline noise will increase
C) Both "fuel economy will be reduced" and "driveline noise will increase"
D) Nothing-this is the normal position

Question 60

Technician A says wheel bearings on 4WD vehicles are permanently sealed and lubricated and do not require disassembly and service after the hubs have been submerged in water. Technician B says a frequent cause of wheel bearing failure is the use of oversized tires mounted on wheels with substantial offset. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 61

____________________ are checked by grasping each front tire at the front and rear and pushing the wheel inward and outward. Then grasping the tire at the top and bottom and pushing the wheel inward and outward.

Question 62

A 4WD transfer case engaged in 2-high or 4-high always provides power to the ____________________ wheels.

Question 63

Selective ____________________ are used to set the transfer case shaft assembly end play.

Question 64

When should the interaxle differential lockup be applied?

Question 65

Identify two disadvantages of 4WD systems, when compared to 2WD systems.

Question 66

The result of having a different gear ratio in the front axle than in the rear axle will cause a phenomenon called driveline ____________________.

Question 67

What is the main advantage of all-wheel drive?

Question 68

The speed sensors used in a 4WD or AWD system are best checked with a ____________________.

Question 69

Identify the main internal components in a conventional transfer case.

Question 70

Some 4WD vehicles that have been adapted from a FWD format use a(n) ____________________ take-off to transmit torque to the rear driveline.

Question 71

A transfer case is constructed somewhat similarly to a manual ____________________.

Question 72

For most driving conditions, the transfer case gear selector in a 4WD vehicle should be in the ____________________ position.

Question 73

What is the disadvantage of manual locking hubs?

Question 74

When the plates of a viscous coupling (clutch) rotate at different speeds, the plates ____________________ the fluid.

Question 75

Describe the operation of a viscous clutch.

Question 76

When a difference in speed of ____________________ percent exists between the input and output of a viscous clutch the clutch, will lock the input to the output.

Question 77

If additional torque is required at all four wheels in a 4WD vehicle, the gear selector should be placed in the ____________________ position.

Question 78

The ____________________ allows the front and rear axles to turn at slightly different speeds when the vehicle is in 4WD mode.

Question 79

Identify the gear selector positions available in a conventional 4WD transfer case.

Question 80

A transfer case splits driveline torque to the front and rear axles through the use of a(n) ____________________ or gear arrangement.