Drive Axle and Carrier Fundamentals and Service (Off Road) - Part B

Question 1

What are the five functions of the drive axle assembly?

Answer 1

1. a) The drive axle assembly must withstand and support the weight of the vehicle and load that has been passed through the suspension system to the drive axle assemblies.
   b) The drive axle assembly provides a gear reduction in the basic vehicle powertrain.
   c) The drive axle assembly must change the direction of torque by 90°.
   d) The drive axle must transfer torque evenly between the two wheel assemblies it is driving while allowing for a difference in speed between the two.
   e) The operator is able to lock the wheel ends in a low traction situation.

Question 2

2. The main function of the carrier housing is to:
   a) house the axle shafts.
   b) secure the suspension components.
   c) withstand the weight of the vehicle.
   d) hold the internal gear components.

Answer 2

d) hold the internal gear components.

Question 3

3. The pinion bearing cage is always a removable component of the carrier housing.
   a) true
   b) false

Answer 3

3. b) false; It may be a removable piece of the carrier housing or an integral
   component.

Question 4

4. The overhung pinion differs from the straddle mount in that it has a short stub that extends past the end of the pinion gear.
   a) true
   b) false

Answer 4

4. b) false; The overhung mount pinion can be distinguished by the flat surface at
   the end of the pinion gear. A short stub shaft that extends past the end of the pinion gear characterizes the straddle mount pinion design.

Question 5

5. The input drive pinion is in constant mesh with the:
   a) differential pinions.
   b) axle side gears.
   c) bevel gear.
   d) differential case.

Answer 5

5. c) bevel gear.

Question 6

6. What is the main purpose of the thrust screw?

Answer 6

6. The thrust screw prevents the bevel gear from deflecting away from the input pinion
   during heavy torque loads.

Question 7

7. The bevel gear is bolted directly to the:
   a) carrier housing.
   b) differential pinions.
   c) plain case half.
   d) flanged case half.

Answer 7

7. d) flanged case half.

Question 8

8. The differential pinions are driven by the:
   a) cross shafts.
   b) axle side gears.
   c) bevel gear.
   d) case halves.

Answer 8

8. a) cross shafts.

Question 9

9. The most common differential carrier assembly used today is the:
   a) single speed single reduction.
   b) single speed double reduction.
   c) two speed double reduction.
   d) planetary carrier.

Answer 9

9. a) single speed single reduction.

Question 10

10. Which components are attached to the drive axle housing?
    a) suspension components
    b) wheels tires and hubs
    c) carrier housing
    d) all of the above

Answer 10

10. d) all of the above

Question 11

11. Number the following components in the path-of-power through the single speed, single reduction carrier assembly. Begin with the input shaft yoke and end with the wheel assemblies.

input shaft yoke
differential cross shaft
differential case
axle shafts
input drive pinion
bevel gear
axle side gears differential pinions
differential pinions
wheel assemblies

Answer 11

11. 
input shaft yoke 1
differential cross shaft   5
differential case 4
axle shafts 8
input drive pinion 2
bevel gear  3
axle side gears differential pinions7
differential pinons 6
wheel assemblies  9

Question 12

12. The torque available to the wheel with good traction in a wheel spin condition is:
    a) full torque.
    b) half of full torque.
    c) twice that of the torque to the spinning wheel.
    d) the same as the torque to the spinning wheel.

Answer 12

12. d) the same as the torque to the spinning wheel.

Question 13

13. When a vehicle is turning a comer, the differential assembly allows the:
    a) inner drive wheel to rotate faster than the outer drive wheel.
    b) outer drive wheel to rotate faster than the inner drive wheel.
    c) bevel gear to rotate at the same speed as the outer drive wheel.
    d) bevel gear to rotate at the same speed as the inner drive wheel.

Answer 13

13. b) outer drive wheel to rotate faster than the inner drive wheel.

Question 14

14. Semi-floating axle shafts can be removed from a vehicle when the weight of the
    vehicle is on the drive wheels.
    a) true
    b) false

Answer 14

14. b) false; To remove the semi-floating axles, the vehicle weight must be supported
    and the drive wheels must be off the ground.

Question 15

15. Transfer cases always incorporate a differential to allow for a difference in speed between the two output shafts
    a) true
    b) false

Answer 15

15. b) false; Certain transfer cases have no differential and force the output shafts to
    rotate at equal speeds.

Question 16

16. A planetary differential allows for torque to be proportioned between its outputs
    a) true
    b) false

Answer 16

16. a) True; The planetary differential discussed in this module allows a 60/40 torque
split between the output shafts.

Question 17

17. Why is it preferable to allow the operator control over the differential lock?

Answer 17

17. To minimize tire spin and maximize traction in low traction conditions, but to also
    allow differential action in high traction conditions and while hauling at higher speeds.